Do not link with debug libc on win32 when using cross compile libs. Add delete methods to dstring. Fixes to macOS aarch64 codegen. Use glibc backtrace when available. Add load_* methods to file. The cast (int[8])int_slice[:8] now works.

Fixes to the grammar.
Improve "const" error message #1079 .
2026-02-27 12:01:16 +00:00 · 2023-12-08 18:59:57 +01:00 · 2023-11-26 20:06:38 +01:00 · 2023-11-22 19:12:04 +01:00 · 2023-11-22 19:12:04 +01:00 · 2023-11-20 23:48:18 +01:00
856 changed files with 53129 additions and 34959 deletions
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -7,7 +7,7 @@ on:
    branches: [ master ]

 env:
-  LLVM_RELEASE_VERSION: 15
+  LLVM_RELEASE_VERSION: 16

 jobs:

@@ -23,7 +23,7 @@ jobs:
      run:
        shell: cmd
    steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4

      - name: CMake
        run: |
@@ -34,15 +34,23 @@ jobs:
        run: |
          cd resources
          ..\build\${{ matrix.build_type }}\c3c.exe compile-run examples\hello_world_many.c3
+          ..\build\${{ matrix.build_type }}\c3c.exe compile-run examples\time.c3
          ..\build\${{ matrix.build_type }}\c3c.exe compile-run examples\fannkuch-redux.c3
          ..\build\${{ matrix.build_type }}\c3c.exe compile-run examples\contextfree\boolerr.c3
+          ..\build\${{ matrix.build_type }}\c3c.exe compile-run examples\ls.c3
          ..\build\${{ matrix.build_type }}\c3c.exe compile-run examples\load_world.c3
-          
+          ..\build\${{ matrix.build_type }}\c3c.exe compile-run examples\process.c3
+          ..\build\${{ matrix.build_type }}\c3c.exe compile --test -g -O0 --threads 1 --target macos-x64 examples\constants.c3                  
+          ..\build\${{ matrix.build_type }}\c3c.exe compile-run msvc_stack.c3

      - name: Build testproject
        run: |
          cd resources/testproject
-          ..\..\build\${{ matrix.build_type }}\c3c.exe --debug-log run hello_world_win32
+          ..\..\build\${{ matrix.build_type }}\c3c.exe --debug-log --emit-llvm run hello_world_win32
+          dir build\llvm_ir
+          ..\..\build\${{ matrix.build_type }}\c3c.exe clean
+          dir build\llvm_ir
+          

      - name: Build testproject lib
        run: |
@@ -61,7 +69,7 @@ jobs:
      - name: Compile run unit tests
        run: |
          cd test
-          ..\build\${{ matrix.build_type }}\c3c.exe compile-test unit -g1 --safe
+          ..\build\${{ matrix.build_type }}\c3c.exe compile-test unit -O1

      - name: upload artifacts
        uses: actions/upload-artifact@v3
@@ -71,6 +79,7 @@ jobs:

  build-msys2-mingw:
    runs-on: windows-latest
+    # if: ${{ false }}
    strategy:
      # Don't abort runners if a single one fails
      fail-fast: false
@@ -81,29 +90,31 @@ jobs:
      run:
        shell: msys2 {0}
    steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4

      - uses: msys2/setup-msys2@v2
        with:
          msystem: MINGW64
          update: true
-          install: git binutils mingw-w64-x86_64-ninja mingw-w64-x86_64-cmake mingw-w64-x86_64-toolchain mingw-w64-x86_64-python
+          install: git binutils mingw-w64-x86_64-clang mingw-w64-x86_64-ninja mingw-w64-x86_64-cmake mingw-w64-x86_64-toolchain mingw-w64-x86_64-python
      - shell: msys2 {0}
        run: |
-            pacman --noconfirm -U https://mirror.msys2.org/mingw/mingw64/mingw-w64-x86_64-llvm-15.0.3-1-any.pkg.tar.zst
-            pacman --noconfirm -U https://mirror.msys2.org/mingw/mingw64/mingw-w64-x86_64-lld-15.0.3-1-any.pkg.tar.zst
+            pacman --noconfirm -U https://mirror.msys2.org/mingw/mingw64/mingw-w64-x86_64-llvm-17.0.6-1-any.pkg.tar.zst
+            pacman --noconfirm -U https://mirror.msys2.org/mingw/mingw64/mingw-w64-x86_64-lld-17.0.6-1-any.pkg.tar.zst
      - name: CMake
        run: |
-          cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=${{ matrix.build_type }}
+          cmake -B build -G Ninja -DCMAKE_C_COMPILER=clang -DCMAKE_BUILD_TYPE=${{ matrix.build_type }}
          cmake --build build

      - name: Compile and run some examples
        run: |
          cd resources
          ../build/c3c compile-run examples/hello_world_many.c3
+          ../build/c3c compile-run examples/time.c3
          ../build/c3c compile-run examples/fannkuch-redux.c3
          ../build/c3c compile-run examples/contextfree/boolerr.c3
          ../build/c3c compile-run examples/load_world.c3
+          ../build/c3c compile --test -g -O0 --threads 1 --target macos-x64 examples/constants.c3

      - name: Build testproject
        run: |
@@ -127,7 +138,7 @@ jobs:

  build-msys2-clang:
    runs-on: windows-latest
-    if: ${{ false }}
+    #if: ${{ false }}
    strategy:
      # Don't abort runners if a single one fails
      fail-fast: false
@@ -138,7 +149,7 @@ jobs:
      run:
        shell: msys2 {0}
    steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4

      - uses: msys2/setup-msys2@v2
        with:
@@ -155,10 +166,11 @@ jobs:
        run: |
          cd resources
          ../build/c3c compile-run examples/hello_world_many.c3
+          ../build/c3c compile-run examples/time.c3
          ../build/c3c compile-run examples/fannkuch-redux.c3
          ../build/c3c compile-run examples/contextfree/boolerr.c3
          ../build/c3c compile-run examples/load_world.c3
-
+          ../build/c3c compile --test -g -O0 --threads 1 --target macos-x64 examples/constants.c3
      - name: Build testproject
        run: |
          cd resources/testproject
@@ -181,10 +193,128 @@ jobs:
      fail-fast: false
      matrix:
        build_type: [Release, Debug]
-        llvm_version: [15, 16, 17]
+        llvm_version: [15, 16, 17, 18]

    steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
+      - name: Install common deps
+        run: |
+          sudo apt-get install zlib1g zlib1g-dev python3 ninja-build curl
+
+      - name: Install Clang ${{matrix.llvm_version}}
+        run: |
+          wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
+          if [[ "${{matrix.llvm_version}}" < 16 ]]; then
+            sudo apt remove libllvm15
+          fi
+          if [[ "${{matrix.llvm_version}}" < 18 ]]; then
+            sudo add-apt-repository "deb http://apt.llvm.org/focal/ llvm-toolchain-focal-${{matrix.llvm_version}} main"
+            sudo apt-get update
+            sudo apt-get install -y -t llvm-toolchain-focal-${{matrix.llvm_version}} libpolly-${{matrix.llvm_version}}-dev \
+              clang-${{matrix.llvm_version}} llvm-${{matrix.llvm_version}} llvm-${{matrix.llvm_version}}-dev \
+              lld-${{matrix.llvm_version}} liblld-${{matrix.llvm_version}}-dev libmlir-${{matrix.llvm_version}} \
+              libmlir-${{matrix.llvm_version}}-dev mlir-${{matrix.llvm_version}}-tools 
+          else
+            sudo add-apt-repository "deb http://apt.llvm.org/focal/ llvm-toolchain-focal main"
+            sudo apt-get install -y -t llvm-toolchain-focal libpolly-${{matrix.llvm_version}}-dev \
+              clang-${{matrix.llvm_version}} llvm-${{matrix.llvm_version}} llvm-${{matrix.llvm_version}}-dev \
+              lld-${{matrix.llvm_version}} liblld-${{matrix.llvm_version}}-dev libmlir-${{matrix.llvm_version}} \
+              libmlir-${{matrix.llvm_version}}-dev mlir-${{matrix.llvm_version}}-tools 
+          fi
+      - name: CMake
+        run: |
+          cmake -B build \
+                -G Ninja \
+                -DCMAKE_BUILD_TYPE=${{matrix.build_type}} \
+                -DCMAKE_C_COMPILER=clang-${{matrix.llvm_version}} \
+                -DCMAKE_CXX_COMPILER=clang++-${{matrix.llvm_version}} \
+                -DCMAKE_LINKER=lld-link-${{matrix.llvm_version}} \
+                -DCMAKE_OBJCOPY=llvm-objcopy-${{matrix.llvm_version}} \
+                -DCMAKE_STRIP=llvm-strip-${{matrix.llvm_version}} \
+                -DCMAKE_DLLTOOL=llvm-dlltool-${{matrix.llvm_version}} \
+                -DC3_LLVM_VERSION=${{matrix.llvm_version}}
+          cmake --build build
+
+      - name: Compile and run some examples
+        run: |
+          cd resources
+          ../build/c3c compile examples/base64.c3
+          ../build/c3c compile examples/binarydigits.c3
+          ../build/c3c compile examples/brainfk.c3
+          ../build/c3c compile examples/factorial_macro.c3
+          ../build/c3c compile examples/fasta.c3
+          ../build/c3c compile examples/gameoflife.c3
+          ../build/c3c compile examples/hash.c3
+          ../build/c3c compile examples/levenshtein.c3
+          ../build/c3c compile examples/load_world.c3
+          ../build/c3c compile examples/map.c3
+          ../build/c3c compile examples/mandelbrot.c3
+          ../build/c3c compile examples/plus_minus.c3
+          ../build/c3c compile examples/nbodies.c3
+          ../build/c3c compile examples/spectralnorm.c3
+          ../build/c3c compile examples/swap.c3
+          ../build/c3c compile examples/contextfree/boolerr.c3
+          ../build/c3c compile examples/contextfree/dynscope.c3
+          ../build/c3c compile examples/contextfree/guess_number.c3
+          ../build/c3c compile examples/contextfree/multi.c3          
+          ../build/c3c compile examples/contextfree/cleanup.c3          
+          ../build/c3c compile-run examples/hello_world_many.c3
+          ../build/c3c compile-run examples/time.c3
+          ../build/c3c compile-run examples/fannkuch-redux.c3
+          ../build/c3c compile-run examples/contextfree/boolerr.c3
+          ../build/c3c compile-run examples/load_world.c3
+          ../build/c3c compile-run examples/process.c3
+          ../build/c3c compile-run examples/ls.c3
+          ../build/c3c compile-run --system-linker=no linux_stack.c3
+          ../build/c3c compile-run linux_stack.c3
+
+      - name: Compile run unit tests
+        run: |
+          cd test
+          ../build/c3c compile-test unit
+
+      - name: Build testproject
+        run: |
+          cd resources/testproject
+          ../../build/c3c run --debug-log
+
+      - name: Build testproject direct linker
+        run: |
+          cd resources/testproject
+          ../../build/c3c run --debug-log --system-linker=no
+
+      - name: run compiler tests
+        run: |
+          cd test
+          python3 src/tester.py ../build/c3c test_suite/
+
+      - name: bundle_output
+        if: matrix.llvm_version == 16
+        run: |
+          mkdir linux
+          cp -r lib linux
+          cp msvc_build_libraries.py linux
+          cp build/c3c linux
+          tar czf c3-linux-${{matrix.build_type}}.tar.gz linux
+
+      - name: upload artifacts
+        if: matrix.llvm_version == 16
+        uses: actions/upload-artifact@v3
+        with:
+          name: c3-linux-${{matrix.build_type}}
+          path: c3-linux-${{matrix.build_type}}.tar.gz
+
+  build-linux-ubuntu20:
+    runs-on: ubuntu-20.04
+    strategy:
+      # Don't abort runners if a single one fails
+      fail-fast: false
+      matrix:
+        build_type: [Release, Debug]
+        llvm_version: [16]
+
+    steps:
+      - uses: actions/checkout@v4
      - name: Install common deps
        run: |
          sudo apt-get install zlib1g zlib1g-dev python3 ninja-build curl
@@ -197,7 +327,7 @@ jobs:
          else
            sudo add-apt-repository "deb http://apt.llvm.org/focal/ llvm-toolchain-focal main"
          fi
-          sudo apt-get update
+          sudo apt-get update      
          sudo apt-get install -y clang-${{matrix.llvm_version}} llvm-${{matrix.llvm_version}} llvm-${{matrix.llvm_version}}-dev lld-${{matrix.llvm_version}} liblld-${{matrix.llvm_version}}-dev
          sudo apt-get install -y libmlir-${{matrix.llvm_version}} libmlir-${{matrix.llvm_version}}-dev mlir-${{matrix.llvm_version}}-tools 
          sudo apt-get install -y libpolly-${{matrix.llvm_version}}-dev
@@ -218,15 +348,37 @@ jobs:
      - name: Compile and run some examples
        run: |
          cd resources
-          ../build/c3c compile-run examples/hello_world_many.c3
-          ../build/c3c compile-run examples/fannkuch-redux.c3
+          ../build/c3c compile examples/gameoflife.c3
+          ../build/c3c compile examples/levenshtein.c3
+          ../build/c3c compile examples/map.c3
+          ../build/c3c compile examples/mandelbrot.c3
+          ../build/c3c compile examples/plus_minus.c3
+          ../build/c3c compile examples/spectralnorm.c3
+          ../build/c3c compile examples/swap.c3
+          ../build/c3c compile examples/contextfree/guess_number.c3
+          ../build/c3c compile-run examples/hash.c3
+          ../build/c3c compile-run examples/nbodies.c3
          ../build/c3c compile-run examples/contextfree/boolerr.c3
+          ../build/c3c compile-run examples/contextfree/dynscope.c3
+          ../build/c3c compile-run examples/contextfree/multi.c3          
+          ../build/c3c compile-run examples/contextfree/cleanup.c3          
+          ../build/c3c compile-run examples/hello_world_many.c3
+          ../build/c3c compile-run examples/time.c3
+          ../build/c3c compile-run examples/fannkuch-redux.c3
          ../build/c3c compile-run examples/load_world.c3
+          ../build/c3c compile-run examples/base64.c3
+          ../build/c3c compile-run examples/binarydigits.c3
+          ../build/c3c compile-run examples/brainfk.c3
+          ../build/c3c compile-run examples/factorial_macro.c3
+          ../build/c3c compile-run examples/fasta.c3
+          ../build/c3c compile-run examples/process.c3
+          ../build/c3c compile-run --system-linker=no linux_stack.c3
+          ../build/c3c compile-run linux_stack.c3

      - name: Compile run unit tests
        run: |
          cd test
-          ../build/c3c compile-test unit -g1 --safe
+          ../build/c3c compile-test unit

      - name: Build testproject
        run: |
@@ -236,7 +388,7 @@ jobs:
      - name: Build testproject direct linker
        run: |
          cd resources/testproject
-          ../../build/c3c run --debug-log --forcelinker
+          ../../build/c3c run --debug-log --system-linker=no

      - name: run compiler tests
        run: |
@@ -244,21 +396,20 @@ jobs:
          python3 src/tester.py ../build/c3c test_suite/

      - name: bundle_output
-        if: matrix.llvm_version == env.LLVM_RELEASE_VERSION
+        if: matrix.llvm_version == 16
        run: |
          mkdir linux
          cp -r lib linux
          cp msvc_build_libraries.py linux
          cp build/c3c linux
-          tar czf c3-linux-${{matrix.build_type}}.tar.gz linux
+          tar czf c3-ubuntu-20-${{matrix.build_type}}.tar.gz linux

      - name: upload artifacts
-        if: matrix.llvm_version == env.LLVM_RELEASE_VERSION
+        if: matrix.llvm_version == 16
        uses: actions/upload-artifact@v3
        with:
-          name: c3-linux-${{matrix.build_type}}
-          path: c3-linux-${{matrix.build_type}}.tar.gz
-
+          name: c3-ubuntu-20-${{matrix.build_type}}
+          path: c3-ubuntu-20-${{matrix.build_type}}.tar.gz

  build-mac:
    runs-on: macos-latest
@@ -267,12 +418,11 @@ jobs:
      fail-fast: false
      matrix:
        build_type: [Release, Debug]
-        llvm_version: [15]
+        llvm_version: [15, 16]
    steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
      - name: Download LLVM
        run: |
-          brew update 
          brew install llvm@${{ matrix.llvm_version }} ninja curl
          echo "/usr/local/opt/llvm@${{ matrix.llvm_version }}/bin" >> $GITHUB_PATH
          TMP_PATH=$(xcrun --show-sdk-path)/user/include
@@ -291,14 +441,16 @@ jobs:
        run: |
          cd resources
          ../build/c3c compile-run examples/hello_world_many.c3
+          ../build/c3c compile-run examples/time.c3
          ../build/c3c compile-run examples/fannkuch-redux.c3
          ../build/c3c compile-run examples/contextfree/boolerr.c3
+          ../build/c3c compile-run examples/process.c3
          ../build/c3c compile-run examples/load_world.c3

      - name: Compile run unit tests
        run: |
          cd test
-          ../build/c3c compile-test unit -g1 --safe
+          ../build/c3c compile-test unit

      - name: Build testproject
        run: |
@@ -308,7 +460,7 @@ jobs:
      - name: Build testproject direct linker
        run: |
          cd resources/testproject
-          ../../build/c3c run --debug-log --forcelinker
+          ../../build/c3c run --debug-log --system-linker=no

      - name: Build testproject lib
        run: |
@@ -343,7 +495,7 @@ jobs:
    if: github.ref == 'refs/heads/master'

    steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
      - name: delete tag
        continue-on-error: true
        uses: actions/github-script@v6
@@ -426,6 +578,27 @@ jobs:
          asset_name: c3-linux-debug.tar.gz
          asset_content_type: application/gzip

+      - name: upload ubuntu 20
+        uses: actions/upload-release-asset@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ steps.create_release.outputs.upload_url }}
+
+          asset_path: c3-ubuntu-20-Release/c3-ubuntu-20-Release.tar.gz
+          asset_name: c3-ubuntu-20.tar.gz
+          asset_content_type: application/gzip
+
+      - name: upload ubuntu 20 debug
+        uses: actions/upload-release-asset@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ steps.create_release.outputs.upload_url }}
+          asset_path: c3-ubuntu-20-Debug/c3-ubuntu-20-Debug.tar.gz
+          asset_name: c3-ubuntu-20-debug.tar.gz
+          asset_content_type: application/gzip
+
      - name: upload macos
        uses: actions/upload-release-asset@v1
        env:
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,11 +10,20 @@ endif()
 project(c3c VERSION ${CMAKE_MATCH_1})
 message("C3C version: ${CMAKE_PROJECT_VERSION}")

+if (NOT DEFINED CMAKE_INSTALL_LIBDIR)
+    if (MSVC)
+        set(CMAKE_INSTALL_LIBDIR "c:\\c3c\\lib")
+        set(CMAKE_INSTALL_BINDIR "c:\\c3c")
+    else ()
+        set(CMAKE_INSTALL_LIBDIR "/usr/local/lib/c3")
+        set(CMAKE_INSTALL_BINDIR "/usr/local/bin/c3c")
+    endif()
+endif ()
+
 # Enable fetching (for Windows)
 include(FetchContent)
 include(FeatureSummary)

-
 set(CMAKE_FIND_PACKAGE_SORT_ORDER NATURAL)
 set(CMAKE_FIND_PACKAGE_SORT_DIRECTION DEC)

@@ -25,19 +34,24 @@ set(CMAKE_CXX_STANDARD 17)
 if(MSVC)
    set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /O2 /EHsc")
    set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} /O2 /EHsc")
-    set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /Od /Zi /EHsc")
-    set(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} /Od /Zi /EHsc")
+    set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /Od /Zi /EHa")
+    set(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} /Od /Zi /EHa")
 else()
-set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -O3 -fno-exceptions")
-set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -gdwarf-3 -fno-exceptions")
-set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -gdwarf-3 -O3 -fno-exceptions")
-set(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -gdwarf-3 -fno-exceptions")
+    if (true)
+        set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -O3 -fno-exceptions")
+        set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -gdwarf-3 -fno-exceptions")
+        set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -gdwarf-3 -O3 -fno-exceptions")
+        set(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -gdwarf-3 -fno-exceptions")
+    else()
+        set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -gdwarf-3 -O3 -fsanitize=undefined,address -fno-exceptions")
+        set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -gdwarf-3 -O1 -fsanitize=undefined,address -fno-exceptions")
+        set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -gdwarf-3 -O3 -fsanitize=undefined,address -fno-exceptions")
+        set(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -gdwarf-3 -O1 -fsanitize=undefined,address -fno-exceptions")
+        set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -fsanitize=undefined,address -fno-exceptions")
+    endif()
 endif()
-#set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -O1 -fsanitize=undefined")
-#set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -O1 -fsanitize=undefined")
-#set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -gdwarf-3 -O3 -fsanitize=undefined")
-#set(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -gdwarf-3 -fsanitize=undefined")
-#set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -fsanitize=undefined")
+
+option(C3_LINK_DYNAMIC "link dynamically with LLVM/LLD libs")

 set(C3_LLVM_VERSION "auto" CACHE STRING "Use LLVM version [default: auto]")
 option(C3_USE_MIMALLOC "Use built-in mimalloc" OFF)
@@ -61,7 +75,7 @@ if (NOT WIN32)
    find_package(CURL)
 endif()
 if (NOT C3_LLVM_VERSION STREQUAL "auto")
-    if (${C3_LLVM_VERSION} VERSION_LESS 15 OR ${C3_LLVM_VERSION} VERSION_GREATER 17)
+    if (${C3_LLVM_VERSION} VERSION_LESS 15 OR ${C3_LLVM_VERSION} VERSION_GREATER 18)
        message(FATAL_ERROR "LLVM ${C3_LLVM_VERSION} is not supported!")
    endif()
 endif()
@@ -83,15 +97,15 @@ endif()

 if(CMAKE_C_COMPILER_ID STREQUAL "MSVC")
    if (C3_LLVM_VERSION STREQUAL "auto")
-        set(C3_LLVM_VERSION "15")
+        set(C3_LLVM_VERSION "16")
    endif()
    FetchContent_Declare(
            LLVM_Windows
-            URL https://github.com/c3lang/win-llvm/releases/download/llvm_15_0_6/llvm-15.0.6-windows-amd64-msvc17-libcmt.7z
+            URL https://github.com/c3lang/win-llvm/releases/download/llvm_16_0_2/llvm-16.0.2-windows-amd64-msvc17-libcmt.7z
    )
    FetchContent_Declare(
            LLVM_Windows_debug
-            URL https://github.com/c3lang/win-llvm/releases/download/llvm_15_0_6/llvm-15.0.6-windows-amd64-msvc17-libcmt-dbg.7z
+            URL https://github.com/c3lang/win-llvm/releases/download/llvm_16_0_2/llvm-16.0.2-windows-amd64-msvc17-libcmt-dbg.7z
    )
    if(CMAKE_BUILD_TYPE STREQUAL "Debug")
        message("Loading Windows LLVM debug libraries, this may take a while...")
@@ -115,54 +129,75 @@ endif()
 message(STATUS "Found LLVM ${LLVM_PACKAGE_VERSION}")
 message(STATUS "Using LLVMConfig.cmake in: ${LLVM_DIR}")
 message(STATUS "Libraries located in: ${LLVM_LIBRARY_DIRS}")
+
+if(LLVM_ENABLE_RTTI)
+    message(STATUS "LLVM was built with RTTI")
+else()
+    message(STATUS "LLVM was not built with RTTI")
+endif()
+
 include_directories(${LLVM_INCLUDE_DIRS})
 link_directories(${LLVM_LIBRARY_DIRS})
 add_definitions(${LLVM_DEFINITIONS})

-set(LLVM_LINK_COMPONENTS
-        AllTargetsAsmParsers
-        AllTargetsCodeGens
-        AllTargetsDescs
-        AllTargetsDisassemblers
-        AllTargetsInfos
-        Analysis
-        AsmPrinter
-        BitReader
-        Core
-        DebugInfoPDB
-        InstCombine
-        IrReader
-        LibDriver
-        Linker
-        LTO
-        MC
-        MCDisassembler
-        native
-        nativecodegen
-        Object
-        Option
-        ScalarOpts
-        Support
-        Target
-        TransformUtils
-        WindowsManifest
-        WindowsDriver
-)
+if(NOT C3_LINK_DYNAMIC)
+    set(LLVM_LINK_COMPONENTS
+	    AllTargetsAsmParsers
+	    AllTargetsCodeGens
+	    AllTargetsDescs
+	    AllTargetsDisassemblers
+	    AllTargetsInfos
+	    Analysis
+	    AsmPrinter
+	    BitReader
+	    Core
+	    DebugInfoPDB
+	    InstCombine
+	    IrReader
+	    LibDriver
+	    Linker
+	    LTO
+	    MC
+	    MCDisassembler
+	    native
+	    nativecodegen
+	    Object
+	    Option
+	    ScalarOpts
+	    Support
+	    Target
+	    TransformUtils
+	    WindowsManifest
+	    WindowsDriver
+    )
+
+    llvm_map_components_to_libnames(llvm_libs ${LLVM_LINK_COMPONENTS})
+
+    # These don't seem to be reliable on windows.
+    message(STATUS "using find_library")
+    find_library(LLD_COFF NAMES lldCOFF.lib lldCOFF.a liblldCOFF.a PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
+    find_library(LLD_COMMON NAMES lldCommon.lib lldCommon.a liblldCommon.a PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
+    find_library(LLD_ELF NAMES lldELF.lib lldELF.a liblldELF.a PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
+    find_library(LLD_MACHO NAMES lldMachO.lib lldMachO.a liblldMachO.a PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
+    find_library(LLD_MINGW NAMES lldMinGW.lib lldMinGW.a liblldMinGW.a PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
+    find_library(LLD_WASM NAMES lldWasm.lib lldWasm.a liblldWasm.a PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
+else()
+    find_library(LLVM NAMES libLLVM.so PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
+    set(llvm_libs ${LLVM})
+
+    # These don't seem to be reliable on windows.
+    message(STATUS "using find_library")
+    find_library(LLD_COFF NAMES liblldCOFF.so PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
+    find_library(LLD_COMMON NAMES liblldCommon.so PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
+    find_library(LLD_ELF NAMES liblldELF.so PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
+    find_library(LLD_MACHO NAMES liblldMachO.so PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
+    find_library(LLD_MINGW NAMES liblldMinGW.so PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
+    find_library(LLD_WASM NAMES liblldWasm.so PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
+endif()

-llvm_map_components_to_libnames(llvm_libs ${LLVM_LINK_COMPONENTS})
 file(REMOVE_RECURSE ${CMAKE_BINARY_DIR}/lib)
 file(COPY ${CMAKE_SOURCE_DIR}/lib DESTINATION ${CMAKE_BINARY_DIR})

-
-# These don't seem to be reliable on windows.
-message(STATUS "using find_library")
-find_library(LLD_COFF NAMES lldCOFF.lib lldCOFF.a liblldCOFF.a PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
-find_library(LLD_COMMON NAMES lldCommon.lib lldCommon.a liblldCommon.a PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
-find_library(LLD_ELF NAMES lldELF.lib lldELF.a liblldELF.a PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
-find_library(LLD_MACHO NAMES lldMachO.lib lldMachO.a liblldMachO.a PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
-find_library(LLD_MINGW NAMES lldMinGW.lib lldMinGW.a liblldMinGW.a PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
-find_library(LLD_WASM NAMES lldWasm.lib lldWasm.a liblldWasm.a PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
-
 if (${LLVM_PACKAGE_VERSION} VERSION_GREATER_EQUAL 16)
    find_library(LLD_LOONG NAMES libLLVMLoongArchCodeGen.lib libLLVMLoongArchAsmParser.lib libLLVMLoongArchCodeGen.a libLLVMLoongArchAsmParser.a PATHS ${LLVM_LIBRARY_DIRS} NO_DEFAULT_PATH)
    set(lld_libs
@@ -171,12 +206,7 @@ if (${LLVM_PACKAGE_VERSION} VERSION_GREATER_EQUAL 16)
        ${LLD_WASM}
        ${LLD_MINGW}
        ${LLD_ELF}
-        ${LLD_DRIVER}
-        ${LLD_READER_WRITER}
-        ${LLD_LOONG}
        ${LLD_MACHO}
-        ${LLD_YAML}
-        ${LLD_CORE}
        )
 else()
    set(lld_libs
@@ -185,11 +215,7 @@ else()
        ${LLD_WASM}
        ${LLD_MINGW}
        ${LLD_ELF}
-        ${LLD_DRIVER}
-        ${LLD_READER_WRITER}
        ${LLD_MACHO}
-        ${LLD_YAML}
-        ${LLD_CORE}
        )
 endif()

@@ -210,17 +236,15 @@ add_executable(c3c
        src/build/project_creation.c
        src/compiler/ast.c
        src/compiler/bigint.c
-        src/compiler/c_abi_internal.h
        src/compiler/codegen_general.c
        src/compiler/compiler.c
        src/compiler/compiler.h
        src/compiler/context.c
        src/compiler/copying.c
        src/compiler/diagnostics.c
-        src/compiler/dwarf.h
-        src/compiler/enums.h
        src/compiler/float.c
        src/compiler/headers.c
+        src/compiler/json_output.c
        src/compiler/lexer.c
        src/compiler/libraries.c
        src/compiler/linker.c
@@ -386,12 +410,10 @@ else()
    target_link_options(c3c PRIVATE -pthread)
    target_compile_options(c3c PRIVATE -pthread -Wall -Werror -Wno-unknown-pragmas -Wno-unused-result
            -Wno-unused-function -Wno-unused-variable -Wno-unused-parameter)
-    if (WIN32)
-        target_compile_definitions(c3c PRIVATE USE_PTHREAD=1)
-    endif()
 endif()


 install(TARGETS c3c DESTINATION bin)
+install(DIRECTORY lib/ DESTINATION lib/c3)

 feature_summary(WHAT ALL)
--- a/README.md
+++ b/README.md
@@ -54,7 +54,8 @@ fn void Stack.push(Stack* this, Type element)
    if (this.capacity == this.size)
    {
        this.capacity *= 2;
-        this.elems = mem::realloc(this.elems, Type.sizeof * this.capacity);
+		if (this.capacity < 16) this.capacity = 16;
+        this.elems = realloc(this.elems, Type.sizeof * this.capacity);
    }
    this.elems[this.size++] = element;
 }
@@ -78,20 +79,20 @@ import stack;

 // Define our new types, the first will implicitly create 
 // a complete copy of the entire Stack module with "Type" set to "int"
-define IntStack = Stack<int>;
+def IntStack = Stack(<int>);
 // The second creates another copy with "Type" set to "double"
-define DoubleStack = Stack<double>;
+def DoubleStack = Stack(<double>);

-// If we had added "define IntStack2 = Stack<int>"
+// If we had added "define IntStack2 = Stack(<int>)"
 // no additional copy would have been made (since we already
-// have an parameterization of Stack<int>) so it would
+// have an parameterization of Stack(<int>)) so it would
 // be same as declaring IntStack2 an alias of IntStack

 // Importing an external C function is straightforward
 // here is an example of importing libc's printf:
 extern fn int printf(char* format, ...);

-fn void test()
+fn void main()
 {
    IntStack stack;
    // Note that C3 uses zero initialization by default
@@ -111,12 +112,12 @@ fn void test()
    dstack.push(2.3);
    dstack.push(3.141);
    dstack.push(1.1235);
-    // Prints pop: 1.1235
+    // Prints pop: 1.123500
    printf("pop: %f\n", dstack.pop());
 }
 ```

-### In what ways do C3 differ from C?
+### In what ways does C3 differ from C?

 - No mandatory header files
 - New semantic macro system
@@ -130,17 +131,15 @@ fn void test()
 - Value methods
 - Associated enum data
 - No preprocessor
- Less undefined behaviour and runtime checks in "safe" mode
+- Less undefined behaviour and added runtime checks in "safe" mode
 - Limited operator overloading to enable userland dynamic arrays
 - Optional pre and post conditions

 ### Current status

-The current version of the compiler is alpha release 0.4.
+The current stable version of the compiler is **version 0.5**.

-Design work on C3 complete aside from fleshing out details, such as
-inline asm. As the standard library work progresses, changes and improvements
-to the language will happen continuously.
+The upcoming 0.6 release will focus on expanding the standard library.
 Follow the issues [here](https://github.com/c3lang/c3c/issues).

 If you have suggestions on how to improve the language, either [file an issue](https://github.com/c3lang/c3c/issues) 
@@ -148,7 +147,38 @@ or discuss C3 on its dedicated Discord: [https://discord.gg/qN76R87](https://dis

 The compiler is currently verified to compile on Linux, Windows and MacOS.

+**Support matrix**

+| Platform                 | Native C3 compiler available? | Target supported        | Stack trace | Threads  | Sockets  | Inline asm |
+|--------------------------|-------------------------------|-------------------------|-------------|----------|----------|------------|
+| Win32 x64                | Yes                           | Yes + cross compilation | Yes         | Yes      | Yes      | Yes*       |
+| Win32 Aarch64            | Untested                      | Untested                | Untested    | Untested | Untested | Yes*       |
+| MacOS x64                | Yes                           | Yes + cross compilation | Yes         | Yes      | Yes      | Yes*       |
+| MacOS Aarch64            | Yes                           | Yes + cross compilation | Yes         | Yes      | Yes      | Yes*       |
+| iOS Aarch64              | No                            | Untested                | Untested    | Yes      | Yes      | Yes*       |
+| Linux x86                | Yes                           | Yes                     | Yes         | Yes      | Yes      | Yes*       |
+| Linux x64                | Yes                           | Yes                     | Yes         | Yes      | Yes      | Yes*       |
+| Linux Aarch64            | Yes                           | Yes                     | Yes         | Yes      | Yes      | Yes*       |
+| Linux Riscv32            | Yes                           | Yes                     | Yes         | Yes      | Yes      | Untested   |
+| Linux Riscv64            | Yes                           | Yes                     | Yes         | Yes      | Yes      | Untested   |
+| ELF freestanding x86     | No                            | Untested                | No          | No       | No       | Yes*       |
+| ELF freestanding x64     | No                            | Untested                | No          | No       | No       | Yes*       |
+| ELF freestanding Aarch64 | No                            | Untested                | No          | No       | No       | Yes*       |
+| ELF freestanding Riscv64 | No                            | Untested                | No          | No       | No       | Untested   |
+| ELF freestanding Riscv32 | No                            | Untested                | No          | No       | No       | Untested   |
+| FreeBSD x86              | Untested                      | Untested                | No          | Yes      | Untested | Yes*       |
+| FreeBSD x64              | Untested                      | Untested                | No          | Yes      | Untested | Yes*       |
+| NetBSD x86               | Untested                      | Untested                | No          | Yes      | Untested | Yes*       |
+| NetBSD x64               | Untested                      | Untested                | No          | Yes      | Untested | Yes*       |
+| OpenBSD x86              | Untested                      | Untested                | No          | Yes      | Untested | Yes*       |
+| OpenBSD x64              | Untested                      | Untested                | No          | Yes      | Untested | Yes*       |
+| MCU x86                  | No                            | Untested                | No          | No       | No       | Yes*       |
+| Wasm32                   | No                            | Yes                     | No          | No       | No       | No         |
+| Wasm64                   | No                            | Untested                | No          | No       | No       | No         |
+
+*\* Inline asm is still a work in progress*
+
+More platforms will be supported in the future.

 #### What can you help with?

@@ -183,8 +213,18 @@ The compiler is currently verified to compile on Linux, Windows and MacOS.
 4. Run `./c3c`.

 #### Installing on Arch Linux
-There is an AUR package for the c3c compiler : [c3c-git](https://aur.archlinux.org/packages/c3c-git)  
-You can use your AUR package manager or clone it manually:
+There is an AUR package for the c3c compiler : [c3c-git](https://aur.archlinux.org/packages/c3c-git).
+
+Due to some issues with the LLVM packaged for Arch Linux, the AUR package will download and use LLVM 16 for Ubuntu-23.04 to compile the c3c compiler.
+
+You can use your AUR package manager:
+```sh
+paru -S c3c-git
+# or yay -S c3c-git
+# or aura -A c3c-git
+```
+
+Or clone it manually:
 ```sh
 git clone https://aur.archlinux.org/c3c-git.git
 cd c3c-git
@@ -309,6 +349,6 @@ Editor plugins can be found at https://github.com/c3lang/editor-plugins.
 1. Write the test, either adding to existing test files in `/test/unit/` or add
   a new file. (If testing the standard library, put it in the `/test/unit/stdlib/` subdirectory).
 2. Make sure that the test functions have the `@test` attribute. 
-3. Run tests and see that they pass. (Recommended settings: `c3c compile-test --safe -g1 -O0 test/unit`.
+3. Run tests and see that they pass. (Recommended settings: `c3c compile-test -O0 test/unit`.
   - in this example `test/unit/` is the relative path to the test directory, so adjust as required)
-4. Make a pull request for the new tests.
+4. Make a pull request for the new tests.
--- a/build-with-docker.sh
+++ b/build-with-docker.sh
@@ -21,7 +21,6 @@ if type podman 2>/dev/null >/dev/null; then
 fi

 if [ $config == "Debug" ]; then
-echo "debug???"
    CMAKE_BUILD_TYPE=Debug
 else
    CMAKE_BUILD_TYPE="$config"
--- a/lib/std/ascii.c3
+++ b/lib/std/ascii.c3
@@ -53,6 +53,10 @@ fn bool char.is_blank(char c) => is_blank_m(c);
 fn bool char.is_cntrl(char c) => is_cntrl_m(c);
 fn char char.to_lower(char c) => (char)to_lower_m(c);
 fn char char.to_upper(char c) => (char)to_upper_m(c);
+/**
+ * @require c.is_xdigit()
+ **/
+fn char char.from_hex(char c) => c.is_digit() ? c - '0' : 10 + (c | 0x20) - 'a';

 fn bool uint.in_range(uint c, uint start, uint len) => in_range_m(c, start, len);
 fn bool uint.is_lower(uint c) => is_lower_m(c);
--- a/lib/std/atomic.c3
+++ b/lib/std/atomic.c3
@@ -1,5 +1,520 @@
-// Copyright (c) 2021 Christoffer Lerno. All rights reserved.
+// Copyright (c) 2023 Eduardo José Gómez Hernández. All rights reserved.
 // Use of this source code is governed by the MIT license
 // a copy of which can be found in the LICENSE_STDLIB file.
-module std::atomic;
+module std::atomic::types(<Type>);

+struct Atomic
+{
+	Type data;
+}
+
+/**
+ * Loads data atomically, by default this uses SEQ_CONSISTENT ordering.
+ *
+ * @param ordering "The ordering, cannot be release or acquire-release."
+ * @require ordering != RELEASE && ordering != ACQUIRE_RELEASE : "Release and acquire-release are not valid for load"
+ **/
+macro Type Atomic.load(&self, AtomicOrdering ordering = SEQ_CONSISTENT)
+{
+	Type* data = &self.data;
+	switch(ordering)
+	{
+		case NOT_ATOMIC: return $$atomic_load(data, false, AtomicOrdering.NOT_ATOMIC.ordinal);
+		case UNORDERED: return $$atomic_load(data, false, AtomicOrdering.UNORDERED.ordinal);
+		case RELAXED: return $$atomic_load(data, false, AtomicOrdering.RELAXED.ordinal);
+		case ACQUIRE: return $$atomic_load(data, false, AtomicOrdering.ACQUIRE.ordinal);
+		case SEQ_CONSISTENT: return $$atomic_load(data, false, AtomicOrdering.SEQ_CONSISTENT.ordinal);
+		case ACQUIRE_RELEASE:
+		case RELEASE: unreachable("Invalid ordering.");
+	}
+}
+/**
+ * Stores data atomically, by default this uses SEQ_CONSISTENT ordering.
+ *
+ * @param ordering "The ordering, cannot be acquire or acquire-release."
+ * @require ordering != ACQUIRE && ordering != ACQUIRE_RELEASE : "Acquire and acquire-release are not valid for store"
+ **/
+macro void Atomic.store(&self, Type value, AtomicOrdering ordering = SEQ_CONSISTENT)
+{
+	Type* data = &self.data;
+	switch(ordering) 
+	{
+		case NOT_ATOMIC: $$atomic_store(data, value, false, AtomicOrdering.NOT_ATOMIC.ordinal);
+		case UNORDERED: $$atomic_store(data, value, false, AtomicOrdering.UNORDERED.ordinal);
+		case RELAXED: $$atomic_store(data, value, false, AtomicOrdering.RELAXED.ordinal);
+		case RELEASE: $$atomic_store(data, value, false, AtomicOrdering.RELEASE.ordinal);
+		case SEQ_CONSISTENT: $$atomic_store(data, value, false, AtomicOrdering.SEQ_CONSISTENT.ordinal);
+		case ACQUIRE_RELEASE:
+		case ACQUIRE: unreachable("Invalid ordering.");
+	}
+}
+
+macro Type Atomic.add(&self, Type value, AtomicOrdering ordering = SEQ_CONSISTENT)
+{
+	Type* data = &self.data;
+	return @atomic_exec(atomic::fetch_add, data, value, ordering);
+}
+
+macro Type Atomic.sub(&self, Type value, AtomicOrdering ordering = SEQ_CONSISTENT)
+{
+	Type* data = &self.data;
+	return @atomic_exec(atomic::fetch_sub, data, value, ordering);
+}
+
+macro Type Atomic.mul(&self, Type value, AtomicOrdering ordering = SEQ_CONSISTENT)
+{
+	Type* data = &self.data;
+	return @atomic_exec(atomic::fetch_mul, data, value, ordering);
+}
+
+macro Type Atomic.div(&self, Type value, AtomicOrdering ordering = SEQ_CONSISTENT)
+{
+	Type* data = &self.data;
+	return @atomic_exec(atomic::fetch_div, data, value, ordering);
+}
+
+macro Type Atomic.max(&self, Type value, AtomicOrdering ordering = SEQ_CONSISTENT)
+{
+	Type* data = &self.data;
+	return @atomic_exec(atomic::fetch_div, data, value, ordering);
+}
+
+macro Type Atomic.min(&self, Type value, AtomicOrdering ordering = SEQ_CONSISTENT)
+{
+	Type* data = &self.data;
+	return @atomic_exec(atomic::fetch_min, data, value, ordering);
+}
+
+macro Type Atomic.or(&self, uint value, AtomicOrdering ordering = SEQ_CONSISTENT) @if(!types::is_float(Type))
+{
+	Type* data = &self.data;
+	return @atomic_exec(atomic::fetch_or, data, value, ordering);
+}
+
+fn Type Atomic.xor(&self, uint value, AtomicOrdering ordering = SEQ_CONSISTENT) @if(!types::is_float(Type))
+{
+	Type* data = &self.data;
+	return @atomic_exec(atomic::fetch_xor, data, value, ordering);
+}
+
+macro Type Atomic.and(&self, uint value, AtomicOrdering ordering = SEQ_CONSISTENT) @if(!types::is_float(Type))
+{
+	Type* data = &self.data;
+	return @atomic_exec(atomic::fetch_and, data, value, ordering);
+}
+
+macro Type Atomic.shift_right(&self, uint amount, AtomicOrdering ordering = SEQ_CONSISTENT) @if(!types::is_float(Type))
+{
+	Type* data = &self.data;
+	return @atomic_exec(atomic::fetch_shift_right, data, amount, ordering);
+}
+
+macro Type Atomic.shift_left(&self, uint amount, AtomicOrdering ordering = SEQ_CONSISTENT) @if(!types::is_float(Type))
+{
+	Type* data = &self.data;
+	return @atomic_exec(atomic::fetch_shift_left, data, amount, ordering);
+}
+
+macro @atomic_exec(#func, data, value, ordering) @local
+{
+	switch(ordering) 
+	{
+		case RELAXED: return #func(data, value, RELAXED);
+		case ACQUIRE: return #func(data, value, ACQUIRE);
+		case RELEASE: return #func(data, value, RELEASE);
+		case ACQUIRE_RELEASE: return #func(data, value, ACQUIRE_RELEASE);
+		case SEQ_CONSISTENT: return #func(data, value, SEQ_CONSISTENT);
+		default: assert(false, "Ordering may not be non-atomic or unordered.");
+	}
+}
+
+module std::atomic;
+import std::math;
+
+/**
+ * @param [&in] ptr "the variable or dereferenced pointer to the data."
+ * @param [in] y "the value to be added to ptr."
+ * @param $ordering "atomic ordering of the load, defaults to SEQ_CONSISTENT"
+ * @return "returns the old value of ptr"
+ *
+ * @require !$alignment || math::is_power_of_2($alignment) "Alignment must be a power of two."
+ * @require types::is_int($typeof(*ptr)) || types::is_float($typeof(*ptr)) "Only integer/float pointers may be used."
+ * @require $ordering != AtomicOrdering.NOT_ATOMIC && $ordering != AtomicOrdering.UNORDERED "Acquire ordering is not valid."
+ **/
+macro fetch_add(ptr, y, AtomicOrdering $ordering = SEQ_CONSISTENT, bool $volatile = false, usz $alignment = 0)
+{
+	$if $alignment == 0:
+		$alignment = $typeof(*ptr).sizeof;
+	$endif
+	return $$atomic_fetch_add(ptr, y, $volatile, $ordering.ordinal, $alignment);
+}
+
+/**
+ * @param [&in] ptr "the variable or dereferenced pointer to the data."
+ * @param [in] y "the value to be added to ptr."
+ * @param $ordering "atomic ordering of the load, defaults to SEQ_CONSISTENT"
+ * @return "returns the old value of ptr"
+ * 
+ * @require !$alignment || math::is_power_of_2($alignment) "Alignment must be a power of two."
+ * @require types::is_int($typeof(*ptr)) || types::is_float($typeof(*ptr)) "Only integer/float pointers may be used."
+ * @require $ordering != AtomicOrdering.NOT_ATOMIC && $ordering != AtomicOrdering.UNORDERED "Acquire ordering is not valid."
+ **/
+macro fetch_sub(ptr, y, AtomicOrdering $ordering = SEQ_CONSISTENT, bool $volatile = false, usz $alignment = 0)
+{
+	$if $alignment == 0:
+		$alignment = $typeof(*ptr).sizeof;
+	$endif
+	return $$atomic_fetch_sub(ptr, y, $volatile, $ordering.ordinal, $alignment);
+}
+
+/**
+ * @param [&in] ptr "the variable or dereferenced pointer to the data."
+ * @param [in] y "the value to be added to ptr."
+ * @param $ordering "atomic ordering of the load, defaults to SEQ_CONSISTENT"
+ * @return "returns the old value of ptr"
+ * 
+ * @require types::is_int($typeof(*ptr)) || types::is_float($typeof(*ptr)) "Only integer/float pointers may be used."
+ * @require $ordering != AtomicOrdering.NOT_ATOMIC && $ordering != AtomicOrdering.UNORDERED "Acquire ordering is not valid."
+ **/
+macro fetch_mul(ptr, y, AtomicOrdering $ordering = SEQ_CONSISTENT)
+{
+	var $load_ordering = $ordering;
+	$if $ordering == RELEASE || $ordering == ACQUIRE_RELEASE:
+	    $load_ordering = AtomicOrdering.SEQ_CONSISTENT;
+	$endif
+	
+	var $StorageType = $typefrom(types::lower_to_atomic_compatible_type($typeof(*ptr)));
+
+	$StorageType* storage_ptr = ($StorageType*)ptr;
+
+	$typeof(*ptr) old_value;
+	$typeof(*ptr) new_value;
+
+	$StorageType storage_old_value;
+	$StorageType storage_new_value;
+
+
+	do {
+		storage_old_value = $$atomic_load(storage_ptr, false, $load_ordering.ordinal);
+		old_value = bitcast(storage_old_value, $typeof(*ptr));
+		new_value = old_value * y;
+		storage_new_value = bitcast(new_value, $StorageType);
+	} while (mem::compare_exchange(storage_ptr, storage_old_value, storage_new_value, $ordering, $load_ordering) != storage_old_value);
+
+	return old_value;
+}
+
+/**
+ * @param [&in] ptr "the variable or dereferenced pointer to the data."
+ * @param [in] y "the value to be added to ptr."
+ * @param $ordering "atomic ordering of the load, defaults to SEQ_CONSISTENT"
+ * @return "returns the old value of ptr"
+ * 
+* @require types::is_int($typeof(*ptr)) || types::is_float($typeof(*ptr)) "Only integer/float pointers may be used."
+* @require $ordering != AtomicOrdering.NOT_ATOMIC && $ordering != AtomicOrdering.UNORDERED "Acquire ordering is not valid."
+ **/
+macro fetch_div(ptr, y, AtomicOrdering $ordering = SEQ_CONSISTENT)
+{
+	var $load_ordering = $ordering;
+	$if $ordering == RELEASE || $ordering == ACQUIRE_RELEASE:
+	    $load_ordering = AtomicOrdering.SEQ_CONSISTENT;
+	$endif
+	
+	var $StorageType = $typefrom(types::lower_to_atomic_compatible_type($typeof(*ptr)));
+
+	$StorageType* storage_ptr = ($StorageType*)ptr;
+
+	$typeof(*ptr) old_value;
+	$typeof(*ptr) new_value;
+
+	$StorageType storage_old_value;
+	$StorageType storage_new_value;
+	
+	do {
+		storage_old_value = $$atomic_load(storage_ptr, false, $load_ordering.ordinal);
+		old_value = bitcast(storage_old_value, $typeof(*ptr));
+		new_value = old_value / y;
+		storage_new_value = bitcast(new_value, $StorageType);
+	} while (mem::compare_exchange(storage_ptr, storage_old_value, storage_new_value, $ordering, $load_ordering) != storage_old_value);
+
+	return old_value;
+}
+
+/**
+ * @param [&in] ptr "the variable or dereferenced pointer to the data."
+ * @param [in] y "the value to be added to ptr."
+ * @param $ordering "atomic ordering of the load, defaults to SEQ_CONSISTENT"
+ * @return "returns the old value of ptr"
+ * 
+ * @require !$alignment || math::is_power_of_2($alignment) "Alignment must be a power of two."
+ * @require types::is_int($typeof(*ptr)) "Only integer pointers may be used."
+ * @require types::is_int($typeof(y)) "The value for or must be an int"
+ * @require $ordering != AtomicOrdering.NOT_ATOMIC && $ordering != AtomicOrdering.UNORDERED "Acquire ordering is not valid."
+ **/
+macro fetch_or(ptr, y, AtomicOrdering $ordering = SEQ_CONSISTENT, bool $volatile = false, usz $alignment = 0)
+{
+	$if	types::is_int($typeof(*ptr)):
+		return $$atomic_fetch_or(ptr, y, $volatile, $ordering.ordinal, $alignment);
+	$endif
+
+	var $load_ordering = $ordering;
+	$if $ordering == RELEASE || $ordering == ACQUIRE_RELEASE:
+	    $load_ordering = AtomicOrdering.SEQ_CONSISTENT;
+	$endif
+	
+	var $StorageType = $typefrom(types::lower_to_atomic_compatible_type($typeof(*ptr)));
+
+	$StorageType* storage_ptr = ($StorageType*)ptr;
+
+	$typeof(*ptr) old_value;
+	$typeof(*ptr) new_value;
+
+	$StorageType storage_old_value;
+	$StorageType storage_new_value;
+	$StorageType storage_y = ($StorageType)y;
+	
+	do {
+		storage_old_value = $$atomic_load(storage_ptr, false, $load_ordering.ordinal);
+		old_value = bitcast(storage_old_value, $typeof(*ptr));
+		new_value = storage_old_value | storage_y;
+		storage_new_value = bitcast(new_value, $StorageType);
+	} while (mem::compare_exchange(storage_ptr, storage_old_value, storage_new_value, $ordering, $load_ordering) != storage_old_value);
+
+	return old_value;
+}
+
+/**
+ * @param [&in] ptr "the variable or dereferenced pointer to the data."
+ * @param [in] y "the value to be added to ptr."
+ * @param $ordering "atomic ordering of the load, defaults to SEQ_CONSISTENT"
+ * @return "returns the old value of ptr"
+ * 
+ * @require !$alignment || math::is_power_of_2($alignment) "Alignment must be a power of two."
+ * @require types::is_int($typeof(*ptr)) "Only integer pointers may be used."
+ * @require types::is_int($typeof(y)) "The value for or must be an int"
+ * @require $ordering != AtomicOrdering.NOT_ATOMIC && $ordering != AtomicOrdering.UNORDERED "Acquire ordering is not valid."
+ **/
+macro fetch_xor(ptr, y, AtomicOrdering $ordering = SEQ_CONSISTENT, bool $volatile = false, usz $alignment = 0)
+{
+	$if	types::is_int($typeof(*ptr)):
+		return $$atomic_fetch_xor(ptr, y, $volatile, $ordering.ordinal, $alignment);
+	$endif
+
+	var $load_ordering = $ordering;
+	$if $ordering == RELEASE || $ordering == ACQUIRE_RELEASE:
+	    $load_ordering = AtomicOrdering.SEQ_CONSISTENT;
+	$endif
+	
+	var $StorageType = $typefrom(types::lower_to_atomic_compatible_type($typeof(*ptr)));
+
+	$StorageType* storage_ptr = ($StorageType*)ptr;
+
+	$typeof(*ptr) old_value;
+	$typeof(*ptr) new_value;
+
+	$StorageType storage_old_value;
+	$StorageType storage_new_value;
+	$StorageType storage_y = ($StorageType)y;
+	
+	do {
+		storage_old_value = $$atomic_load(storage_ptr, false, $load_ordering.ordinal);
+		old_value = bitcast(storage_old_value, $typeof(*ptr));
+		new_value = storage_old_value ^ storage_y;
+		storage_new_value = bitcast(new_value, $StorageType);
+	} while (mem::compare_exchange(storage_ptr, storage_old_value, storage_new_value, $ordering, $load_ordering) != storage_old_value);
+
+	return old_value;
+}
+
+/**
+ * @param [&in] ptr "the variable or dereferenced pointer to the data."
+ * @param [in] y "the value to be added to ptr."
+ * @param $ordering "atomic ordering of the load, defaults to SEQ_CONSISTENT"
+ * @return "returns the old value of ptr"
+ * 
+ * @require !$alignment || math::is_power_of_2($alignment) "Alignment must be a power of two."
+ * @require types::is_int($typeof(*ptr)) "Only integer pointers may be used."
+ * @require types::is_int($typeof(y)) "The value for or must be an int"
+ * @require $ordering != AtomicOrdering.NOT_ATOMIC && $ordering != AtomicOrdering.UNORDERED "Acquire ordering is not valid."
+ **/
+macro fetch_and(ptr, y, AtomicOrdering $ordering = SEQ_CONSISTENT, bool $volatile = false, usz $alignment = 0)
+{
+	$if	types::is_int($typeof(*ptr)):
+		return $$atomic_fetch_and(ptr, y, $volatile, $ordering.ordinal, $alignment);
+	$endif
+
+	var $load_ordering = $ordering;
+	$if $ordering == RELEASE || $ordering == ACQUIRE_RELEASE:
+	    $load_ordering = AtomicOrdering.SEQ_CONSISTENT;
+	$endif
+	
+	var $StorageType = $typefrom(types::lower_to_atomic_compatible_type($typeof(*ptr)));
+
+	$StorageType* storage_ptr = ($StorageType*)ptr;
+
+	$typeof(*ptr) old_value;
+	$typeof(*ptr) new_value;
+
+	$StorageType storage_old_value;
+	$StorageType storage_new_value;
+	$StorageType storage_y = ($StorageType)y;
+	
+	do {
+		storage_old_value = $$atomic_load(storage_ptr, false, $load_ordering.ordinal);
+		old_value = bitcast(storage_old_value, $typeof(*ptr));
+		new_value = storage_old_value & storage_y;
+		storage_new_value = bitcast(new_value, $StorageType);
+	} while (mem::compare_exchange(storage_ptr, storage_old_value, storage_new_value, $ordering, $load_ordering) != storage_old_value);
+
+	return old_value;
+}
+
+/**
+ * @param [&in] ptr "the variable or dereferenced pointer to the data."
+ * @param [in] y "the value to be added to ptr."
+ * @param $ordering "atomic ordering of the load, defaults to SEQ_CONSISTENT"
+ * @return "returns the old value of ptr"
+ * 
+ * @require types::is_int($typeof(*ptr)) "Only integer pointers may be used."
+ * @require types::is_int($typeof(y)) "The value for or must be an int"
+ * @require $ordering != AtomicOrdering.NOT_ATOMIC && $ordering != AtomicOrdering.UNORDERED "Acquire ordering is not valid."
+ **/
+macro fetch_shift_right(ptr, y, AtomicOrdering $ordering = SEQ_CONSISTENT)
+{
+	var $load_ordering = $ordering;
+	$if $ordering == RELEASE || $ordering == ACQUIRE_RELEASE:
+	    $load_ordering = AtomicOrdering.SEQ_CONSISTENT;
+	$endif
+	
+	var $StorageType = $typefrom(types::lower_to_atomic_compatible_type($typeof(*ptr)));
+
+	$StorageType* storage_ptr = ($StorageType*)ptr;
+
+	$typeof(*ptr) old_value;
+	$typeof(*ptr) new_value;
+
+	$StorageType storage_old_value;
+	$StorageType storage_new_value;
+	$StorageType storage_y = ($StorageType)y;
+	
+	do {
+		storage_old_value = $$atomic_load(storage_ptr, false, $load_ordering.ordinal);
+		old_value = bitcast(storage_old_value, $typeof(*ptr));
+		new_value = storage_old_value >> storage_y;
+		storage_new_value = bitcast(new_value, $StorageType);
+	} while (mem::compare_exchange(storage_ptr, storage_old_value, storage_new_value, $ordering, $load_ordering) != storage_old_value);
+
+	return old_value;
+}
+
+/**
+ * @param [&in] ptr "the variable or dereferenced pointer to the data."
+ * @param [in] y "the value to be added to ptr."
+ * @param $ordering "atomic ordering of the load, defaults to SEQ_CONSISTENT"
+ * @return "returns the old value of ptr"
+ * 
+ * @require types::is_int($typeof(*ptr)) "Only integer pointers may be used."
+ * @require types::is_int($typeof(y)) "The value for or must be an int"
+ * @require $ordering != AtomicOrdering.NOT_ATOMIC && $ordering != AtomicOrdering.UNORDERED "Acquire ordering is not valid."
+ **/
+macro fetch_shift_left(ptr, y, AtomicOrdering $ordering = SEQ_CONSISTENT)
+{
+	var $load_ordering = $ordering;
+	$if $ordering == RELEASE || $ordering == ACQUIRE_RELEASE:
+	    $load_ordering = AtomicOrdering.SEQ_CONSISTENT;
+	$endif
+	
+	var $StorageType = $typefrom(types::lower_to_atomic_compatible_type($typeof(*ptr)));
+
+	$StorageType* storage_ptr = ($StorageType*)ptr;
+
+	$typeof(*ptr) old_value;
+	$typeof(*ptr) new_value;
+
+	$StorageType storage_old_value;
+	$StorageType storage_new_value;
+	$StorageType storage_y = ($StorageType)y;
+	
+	do {
+		storage_old_value = $$atomic_load(storage_ptr, false, $load_ordering.ordinal);
+		old_value = bitcast(storage_old_value, $typeof(*ptr));
+		new_value = storage_old_value << storage_y;
+		storage_new_value = bitcast(new_value, $StorageType);
+	} while (mem::compare_exchange(storage_ptr, storage_old_value, storage_new_value, $ordering, $load_ordering) != storage_old_value);
+
+	return old_value;
+}
+
+/**
+ * @param [&in] ptr "the variable or dereferenced pointer to the data."
+ * @param $ordering "atomic ordering of the load, defaults to SEQ_CONSISTENT"
+ * @return "returns the old value of ptr"
+ * 
+ * @require types::is_int($typeof(*ptr)) "Only integer pointers may be used."
+ * @require $ordering != AtomicOrdering.NOT_ATOMIC && $ordering != AtomicOrdering.UNORDERED "Acquire ordering is not valid."
+ **/
+macro flag_set(ptr, AtomicOrdering $ordering = SEQ_CONSISTENT)
+{
+	$typeof(*ptr) old_value;
+	$typeof(*ptr) new_value = true;
+
+	do {
+		old_value = $$atomic_load(ptr, false, $ordering.ordinal);
+	} while (mem::compare_exchange(ptr, old_value, new_value, $ordering, $load_ordering) != old_value);
+	
+	return old_value;
+}
+
+/**
+ * @param [&in] ptr "the variable or dereferenced pointer to the data."
+ * @param $ordering "atomic ordering of the load, defaults to SEQ_CONSISTENT"
+ * @return "returns the old value of ptr"
+ * 
+ * @require types::is_int($typeof(*ptr)) "Only integer pointers may be used."
+ * @require $ordering != AtomicOrdering.NOT_ATOMIC && $ordering != AtomicOrdering.UNORDERED "Acquire ordering is not valid."
+ **/
+macro flag_clear(ptr, AtomicOrdering $ordering = SEQ_CONSISTENT)
+{
+	$typeof(*ptr) old_value;
+	$typeof(*ptr) new_value = false;
+
+	do {
+		old_value = $$atomic_load(ptr, false, $ordering.ordinal);
+	} while (mem::compare_exchange(ptr, old_value, new_value, $ordering, $load_ordering) != old_value);
+
+	return old_value;
+}
+
+/**
+ * @param [&in] ptr "the variable or dereferenced pointer to the data."
+ * @param [in] y "the value to be added to ptr."
+ * @param $ordering "atomic ordering of the load, defaults to SEQ_CONSISTENT"
+ * @return "returns the old value of ptr"
+ * 
+ * @require types::is_int($typeof(*ptr)) || types::is_float($typeof(*ptr)) "Only integer/float pointers may be used."
+ * @require $ordering != AtomicOrdering.NOT_ATOMIC && $ordering != AtomicOrdering.UNORDERED "Acquire ordering is not valid."
+ **/
+macro fetch_max(ptr, y, AtomicOrdering $ordering = SEQ_CONSISTENT, bool $volatile = false, usz $alignment = 0)
+{
+	$if $alignment == 0:
+		$alignment = $typeof(*ptr).sizeof;
+	$endif
+	return $$atomic_fetch_max(ptr, y, $volatile, $ordering.ordinal, $alignment);
+}
+
+/**
+ * @param [&in] ptr "the variable or dereferenced pointer to the data."
+ * @param [in] y "the value to be added to ptr."
+ * @param $ordering "atomic ordering of the load, defaults to SEQ_CONSISTENT"
+ * @return "returns the old value of ptr"
+ * 
+ * @require types::is_int($typeof(*ptr)) || types::is_float($typeof(*ptr)) "Only integer/float pointers may be used."
+ * @require $ordering != AtomicOrdering.NOT_ATOMIC && $ordering != AtomicOrdering.UNORDERED "Acquire ordering is not valid."
+ **/
+macro fetch_min(ptr, y, AtomicOrdering $ordering = SEQ_CONSISTENT, bool $volatile = false, usz $alignment = 0)
+{
+	$if $alignment == 0:
+		$alignment = $typeof(*ptr).sizeof;
+	$endif
+	return $$atomic_fetch_min(ptr, y, $volatile, $ordering.ordinal, $alignment);
+}
--- a/lib/std/atomic_nolibc.c3
+++ b/lib/std/atomic_nolibc.c3
@@ -0,0 +1,63 @@
+// Copyright (c) 2023 Eduardo José Gómez Hernández. All rights reserved.
+// Use of this source code is governed by the MIT license
+// a copy of which can be found in the LICENSE_STDLIB file.
+module std::atomic;
+
+macro @__atomic_compare_exchange_ordering_failure(ptr, expected, desired, $success, failure, $alignment) {
+	switch(failure)
+	{
+		case AtomicOrdering.RELAXED.ordinal: return $$compare_exchange(ptr, expected, desired, false, false, $success, AtomicOrdering.RELAXED.ordinal, $alignment);
+		case AtomicOrdering.ACQUIRE.ordinal: return $$compare_exchange(ptr, expected, desired, false, false, $success, AtomicOrdering.ACQUIRE.ordinal, $alignment);
+		case AtomicOrdering.SEQ_CONSISTENT.ordinal: return $$compare_exchange(ptr, expected, desired, false, false, $success, AtomicOrdering.SEQ_CONSISTENT.ordinal, $alignment);
+		default: assert(false, "Unrecognized failure ordering");
+	}
+	return 0;
+}
+
+macro @__atomic_compare_exchange_ordering_success(ptr, expected, desired, success, failure, $alignment)
+{
+	switch(success)
+	{
+		case AtomicOrdering.RELAXED.ordinal: return @__atomic_compare_exchange_ordering_failure(ptr, expected, desired, AtomicOrdering.RELAXED.ordinal, failure, $alignment);
+		case AtomicOrdering.ACQUIRE.ordinal: return @__atomic_compare_exchange_ordering_failure(ptr, expected, desired, AtomicOrdering.ACQUIRE.ordinal, failure, $alignment);
+		case AtomicOrdering.RELEASE.ordinal: return @__atomic_compare_exchange_ordering_failure(ptr, expected, desired, AtomicOrdering.RELEASE.ordinal, failure, $alignment);
+		case AtomicOrdering.ACQUIRE_RELEASE.ordinal: return @__atomic_compare_exchange_ordering_failure(ptr, expected, desired, AtomicOrdering.ACQUIRE_RELEASE.ordinal, failure, $alignment);
+		case AtomicOrdering.SEQ_CONSISTENT.ordinal: return @__atomic_compare_exchange_ordering_failure(ptr, expected, desired, AtomicOrdering.SEQ_CONSISTENT.ordinal, failure, $alignment);
+		default: assert(false, "Unrecognized success ordering");
+	}
+	return 0;
+}
+
+fn CInt __atomic_compare_exchange(CInt size, any* ptr, any* expected, any* desired, CInt success, CInt failure) @extern("__atomic_compare_exchange") @export
+{
+	switch (size)
+	{
+		case 1:
+			char* pt = (char*)ptr;
+			char ex = *(char*)expected;
+			char de = *(char*)desired;
+			if (ex == @__atomic_compare_exchange_ordering_success(pt, ex, de, success, failure, 1)) return 1;
+		case 2:
+			short* pt = (short*)ptr;
+			short ex = *(short*)expected;
+			short de = *(short*)desired;
+			if (ex == @__atomic_compare_exchange_ordering_success(pt, ex, de, success, failure, 2)) return 1;
+		case 4:
+			int* pt = (int*)ptr;
+			int ex = *(int*)expected;
+			int de = *(int*)desired;
+			if (ex == @__atomic_compare_exchange_ordering_success(pt, ex, de, success, failure, 4)) return 1;
+		case 8:
+			$if iptr.sizeof >= 8:
+				long* pt = (long*)ptr;
+				long ex = *(long*)expected;
+				long de = *(long*)desired;
+				if (ex == @__atomic_compare_exchange_ordering_success(pt, ex, de, success, failure, 8)) return 1;
+			$else
+				nextcase;
+			$endif
+		default:
+			assert(false, "Unsuported size (%d) for atomic_compare_exchange", size);
+	}
+	return 0;
+}
--- a/lib/std/bits.c3
+++ b/lib/std/bits.c3
@@ -1,6 +1,5 @@
 module std::bits;

-
 /**
 * @require types::is_intlike($typeof(i)) `The input must be an integer or integer vector`
 **/
@@ -11,163 +10,162 @@ macro reverse(i) => $$bitreverse(i);
 **/
 macro bswap(i) @builtin => $$bswap(i);

+macro uint[<*>].popcount(self) => $$popcount(self);
+macro uint[<*>].ctz(self) => $$ctz(self);
+macro uint[<*>].clz(self) => $$clz(self);
+macro uint[<*>] uint[<*>].fshl(hi, uint[<*>] lo, uint[<*>] shift) => $$fshl(hi, lo, shift);
+macro uint[<*>] uint[<*>].fshr(hi, uint[<*>] lo, uint[<*>] shift) => $$fshr(hi, lo, shift);
+macro uint[<*>] uint[<*>].rotl(self, uint[<*>] shift) => $$fshl(self, self, shift);
+macro uint[<*>] uint[<*>].rotr(self, uint[<*>] shift) => $$fshr(self, self, shift);

-macro uint[<*>].popcount(uint[<*>] i) => $$popcount(i);
-macro uint[<*>].ctz(uint[<*>] i) => $$ctz(i);
-macro uint[<*>].clz(uint[<*>] i) => $$clz(i);
-macro uint[<*>] uint[<*>].fshl(uint[<*>] hi, uint[<*>] lo, uint[<*>] shift) => $$fshl(hi, lo, shift);
-macro uint[<*>] uint[<*>].fshr(uint[<*>] hi, uint[<*>] lo, uint[<*>] shift) => $$fshr(hi, lo, shift);
-macro uint[<*>] uint[<*>].rotl(uint[<*>] i, uint[<*>] shift) => $$fshl(i, i, shift);
-macro uint[<*>] uint[<*>].rotr(uint[<*>] i, uint[<*>] shift) => $$fshr(i, i, shift);
+macro int[<*>].popcount(self) => $$popcount(self);
+macro int[<*>].ctz(self) => $$ctz(self);
+macro int[<*>].clz(self) => $$clz(self);
+macro int[<*>] int[<*>].fshl(hi, int[<*>] lo, int[<*>] shift) => $$fshl(hi, lo, shift);
+macro int[<*>] int[<*>].fshr(hi, int[<*>] lo, int[<*>] shift) => $$fshr(hi, lo, shift);
+macro int[<*>] int[<*>].rotl(self, int[<*>] shift) => $$fshl(self, self, shift);
+macro int[<*>] int[<*>].rotr(self, int[<*>] shift) => $$fshr(self, self, shift);

-macro int[<*>].popcount(int[<*>] i) => $$popcount(i);
-macro int[<*>].ctz(int[<*>] i) => $$ctz(i);
-macro int[<*>].clz(int[<*>] i) => $$clz(i);
-macro int[<*>] int[<*>].fshl(int[<*>] hi, int[<*>] lo, int[<*>] shift) => $$fshl(hi, lo, shift);
-macro int[<*>] int[<*>].fshr(int[<*>] hi, int[<*>] lo, int[<*>] shift) => $$fshr(hi, lo, shift);
-macro int[<*>] int[<*>].rotl(int[<*>] i, int[<*>] shift) => $$fshl(i, i, shift);
-macro int[<*>] int[<*>].rotr(int[<*>] i, int[<*>] shift) => $$fshr(i, i, shift);
+macro ushort[<*>].popcount(self) => $$popcount(self);
+macro ushort[<*>].ctz(self) => $$ctz(self);
+macro ushort[<*>].clz(self) => $$clz(self);
+macro ushort[<*>] ushort[<*>].fshl(hi, ushort[<*>] lo, ushort[<*>] shift) => $$fshl(hi, lo, shift);
+macro ushort[<*>] ushort[<*>].fshr(hi, ushort[<*>] lo, ushort[<*>] shift) => $$fshr(hi, lo, shift);
+macro ushort[<*>] ushort[<*>].rotl(self, ushort[<*>] shift) => $$fshl(self, self, shift);
+macro ushort[<*>] ushort[<*>].rotr(self, ushort[<*>] shift) => $$fshr(self, self, shift);

-macro ushort[<*>].popcount(ushort[<*>] i) => $$popcount(i);
-macro ushort[<*>].ctz(ushort[<*>] i) => $$ctz(i);
-macro ushort[<*>].clz(ushort[<*>] i) => $$clz(i);
-macro ushort[<*>] ushort[<*>].fshl(ushort[<*>] hi, ushort[<*>] lo, ushort[<*>] shift) => $$fshl(hi, lo, shift);
-macro ushort[<*>] ushort[<*>].fshr(ushort[<*>] hi, ushort[<*>] lo, ushort[<*>] shift) => $$fshr(hi, lo, shift);
-macro ushort[<*>] ushort[<*>].rotl(ushort[<*>] i, ushort[<*>] shift) => $$fshl(i, i, shift);
-macro ushort[<*>] ushort[<*>].rotr(ushort[<*>] i, ushort[<*>] shift) => $$fshr(i, i, shift);
+macro short[<*>].popcount(self) => $$popcount(self);
+macro short[<*>].ctz(self) => $$ctz(self);
+macro short[<*>].clz(self) => $$clz(self);
+macro short[<*>] short[<*>].fshl(hi, short[<*>] lo, short[<*>] shift) => $$fshl(hi, lo, shift);
+macro short[<*>] short[<*>].fshr(hi, short[<*>] lo, short[<*>] shift) => $$fshr(hi, lo, shift);
+macro short[<*>] short[<*>].rotl(self, short[<*>] shift) => $$fshl(self, self, shift);
+macro short[<*>] short[<*>].rotr(self, short[<*>] shift) => $$fshr(self, self, shift);

-macro short[<*>].popcount(short[<*>] i) => $$popcount(i);
-macro short[<*>].ctz(short[<*>] i) => $$ctz(i);
-macro short[<*>].clz(short[<*>] i) => $$clz(i);
-macro short[<*>] short[<*>].fshl(short[<*>] hi, short[<*>] lo, short[<*>] shift) => $$fshl(hi, lo, shift);
-macro short[<*>] short[<*>].fshr(short[<*>] hi, short[<*>] lo, short[<*>] shift) => $$fshr(hi, lo, shift);
-macro short[<*>] short[<*>].rotl(short[<*>] i, short[<*>] shift) => $$fshl(i, i, shift);
-macro short[<*>] short[<*>].rotr(short[<*>] i, short[<*>] shift) => $$fshr(i, i, shift);
+macro char[<*>].popcount(self) => $$popcount(self);
+macro char[<*>].ctz(self) => $$ctz(self);
+macro char[<*>].clz(self) => $$clz(self);
+macro char[<*>] char[<*>].fshl(hi, char[<*>] lo, char[<*>] shift) => $$fshl(hi, lo, shift);
+macro char[<*>] char[<*>].fshr(hi, char[<*>] lo, char[<*>] shift) => $$fshr(hi, lo, shift);
+macro char[<*>] char[<*>].rotl(self, char[<*>] shift) => $$fshl(self, self, shift);
+macro char[<*>] char[<*>].rotr(self, char[<*>] shift) => $$fshr(self, self, shift);

-macro char[<*>].popcount(char[<*>] i) => $$popcount(i);
-macro char[<*>].ctz(char[<*>] i) => $$ctz(i);
-macro char[<*>].clz(char[<*>] i) => $$clz(i);
-macro char[<*>] char[<*>].fshl(char[<*>] hi, char[<*>] lo, char[<*>] shift) => $$fshl(hi, lo, shift);
-macro char[<*>] char[<*>].fshr(char[<*>] hi, char[<*>] lo, char[<*>] shift) => $$fshr(hi, lo, shift);
-macro char[<*>] char[<*>].rotl(char[<*>] i, char[<*>] shift) => $$fshl(i, i, shift);
-macro char[<*>] char[<*>].rotr(char[<*>] i, char[<*>] shift) => $$fshr(i, i, shift);
+macro ichar[<*>].popcount(self) => $$popcount(self);
+macro ichar[<*>].ctz(self) => $$ctz(self);
+macro ichar[<*>].clz(self) => $$clz(self);
+macro ichar[<*>] ichar[<*>].fshl(hi, ichar[<*>] lo, ichar[<*>] shift) => $$fshl(hi, lo, shift);
+macro ichar[<*>] ichar[<*>].fshr(hi, ichar[<*>] lo, ichar[<*>] shift) => $$fshr(hi, lo, shift);
+macro ichar[<*>] ichar[<*>].rotl(self, ichar[<*>] shift) => $$fshl(self, self, shift);
+macro ichar[<*>] ichar[<*>].rotr(self, ichar[<*>] shift) => $$fshr(self, self, shift);

-macro ichar[<*>].popcount(ichar[<*>] i) => $$popcount(i);
-macro ichar[<*>].ctz(ichar[<*>] i) => $$ctz(i);
-macro ichar[<*>].clz(ichar[<*>] i) => $$clz(i);
-macro ichar[<*>] ichar[<*>].fshl(ichar[<*>] hi, ichar[<*>] lo, ichar[<*>] shift) => $$fshl(hi, lo, shift);
-macro ichar[<*>] ichar[<*>].fshr(ichar[<*>] hi, ichar[<*>] lo, ichar[<*>] shift) => $$fshr(hi, lo, shift);
-macro ichar[<*>] ichar[<*>].rotl(ichar[<*>] i, ichar[<*>] shift) => $$fshl(i, i, shift);
-macro ichar[<*>] ichar[<*>].rotr(ichar[<*>] i, ichar[<*>] shift) => $$fshr(i, i, shift);
+macro ulong[<*>].popcount(self) => $$popcount(self);
+macro ulong[<*>].ctz(self) => $$ctz(self);
+macro ulong[<*>].clz(self) => $$clz(self);
+macro ulong[<*>] ulong[<*>].fshl(hi, ulong[<*>] lo, ulong[<*>] shift) => $$fshl(hi, lo, shift);
+macro ulong[<*>] ulong[<*>].fshr(hi, ulong[<*>] lo, ulong[<*>] shift) => $$fshr(hi, lo, shift);
+macro ulong[<*>] ulong[<*>].rotl(self, ulong[<*>] shift) => $$fshl(self, self, shift);
+macro ulong[<*>] ulong[<*>].rotr(self, ulong[<*>] shift) => $$fshr(self, self, shift);

-macro ulong[<*>].popcount(ulong[<*>] i) => $$popcount(i);
-macro ulong[<*>].ctz(ulong[<*>] i) => $$ctz(i);
-macro ulong[<*>].clz(ulong[<*>] i) => $$clz(i);
-macro ulong[<*>] ulong[<*>].fshl(ulong[<*>] hi, ulong[<*>] lo, ulong[<*>] shift) => $$fshl(hi, lo, shift);
-macro ulong[<*>] ulong[<*>].fshr(ulong[<*>] hi, ulong[<*>] lo, ulong[<*>] shift) => $$fshr(hi, lo, shift);
-macro ulong[<*>] ulong[<*>].rotl(ulong[<*>] i, ulong[<*>] shift) => $$fshl(i, i, shift);
-macro ulong[<*>] ulong[<*>].rotr(ulong[<*>] i, ulong[<*>] shift) => $$fshr(i, i, shift);
+macro long[<*>].popcount(self) => $$popcount(self);
+macro long[<*>].ctz(self) => $$ctz(self);
+macro long[<*>].clz(self) => $$clz(self);
+macro long[<*>] long[<*>].fshl(hi, long[<*>] lo, long[<*>] shift) => $$fshl(hi, lo, shift);
+macro long[<*>] long[<*>].fshr(hi, long[<*>] lo, long[<*>] shift) => $$fshr(hi, lo, shift);
+macro long[<*>] long[<*>].rotl(self, long[<*>] shift) => $$fshl(self, self, shift);
+macro long[<*>] long[<*>].rotr(self, long[<*>] shift) => $$fshr(self, self, shift);

-macro long[<*>].popcount(long[<*>] i) => $$popcount(i);
-macro long[<*>].ctz(long[<*>] i) => $$ctz(i);
-macro long[<*>].clz(long[<*>] i) => $$clz(i);
-macro long[<*>] long[<*>].fshl(long[<*>] hi, long[<*>] lo, long[<*>] shift) => $$fshl(hi, lo, shift);
-macro long[<*>] long[<*>].fshr(long[<*>] hi, long[<*>] lo, long[<*>] shift) => $$fshr(hi, lo, shift);
-macro long[<*>] long[<*>].rotl(long[<*>] i, long[<*>] shift) => $$fshl(i, i, shift);
-macro long[<*>] long[<*>].rotr(long[<*>] i, long[<*>] shift) => $$fshr(i, i, shift);
+macro uint128[<*>].popcount(self) => $$popcount(self);
+macro uint128[<*>].ctz(self) => $$ctz(self);
+macro uint128[<*>].clz(self) => $$clz(self);
+macro uint128[<*>] uint128[<*>].fshl(hi, uint128[<*>] lo, uint128[<*>] shift) => $$fshl(hi, lo, shift);
+macro uint128[<*>] uint128[<*>].fshr(hi, uint128[<*>] lo, uint128[<*>] shift) => $$fshr(hi, lo, shift);
+macro uint128[<*>] uint128[<*>].rotl(self, uint128[<*>] shift) => $$fshl(self, self, shift);
+macro uint128[<*>] uint128[<*>].rotr(self, uint128[<*>] shift) => $$fshr(self, self, shift);

-macro uint128[<*>].popcount(uint128[<*>] i) => $$popcount(i);
-macro uint128[<*>].ctz(uint128[<*>] i) => $$ctz(i);
-macro uint128[<*>].clz(uint128[<*>] i) => $$clz(i);
-macro uint128[<*>] uint128[<*>].fshl(uint128[<*>] hi, uint128[<*>] lo, uint128[<*>] shift) => $$fshl(hi, lo, shift);
-macro uint128[<*>] uint128[<*>].fshr(uint128[<*>] hi, uint128[<*>] lo, uint128[<*>] shift) => $$fshr(hi, lo, shift);
-macro uint128[<*>] uint128[<*>].rotl(uint128[<*>] i, uint128[<*>] shift) => $$fshl(i, i, shift);
-macro uint128[<*>] uint128[<*>].rotr(uint128[<*>] i, uint128[<*>] shift) => $$fshr(i, i, shift);
+macro int128[<*>].popcount(self) => $$popcount(self);
+macro int128[<*>].ctz(self) => $$ctz(self);
+macro int128[<*>].clz(self) => $$clz(self);
+macro int128[<*>] int128[<*>].fshl(hi, int128[<*>] lo, int128[<*>] shift) => $$fshl(hi, lo, shift);
+macro int128[<*>] int128[<*>].fshr(hi, int128[<*>] lo, int128[<*>] shift) => $$fshr(hi, lo, shift);
+macro int128[<*>] int128[<*>].rotl(self, int128[<*>] shift) => $$fshl(self, self, shift);
+macro int128[<*>] int128[<*>].rotr(self, int128[<*>] shift) => $$fshr(self, self, shift);

-macro int128[<*>].popcount(int128[<*>] i) => $$popcount(i);
-macro int128[<*>].ctz(int128[<*>] i) => $$ctz(i);
-macro int128[<*>].clz(int128[<*>] i) => $$clz(i);
-macro int128[<*>] int128[<*>].fshl(int128[<*>] hi, int128[<*>] lo, int128[<*>] shift) => $$fshl(hi, lo, shift);
-macro int128[<*>] int128[<*>].fshr(int128[<*>] hi, int128[<*>] lo, int128[<*>] shift) => $$fshr(hi, lo, shift);
-macro int128[<*>] int128[<*>].rotl(int128[<*>] i, int128[<*>] shift) => $$fshl(i, i, shift);
-macro int128[<*>] int128[<*>].rotr(int128[<*>] i, int128[<*>] shift) => $$fshr(i, i, shift);
+macro uint.popcount(self) => $$popcount(self);
+macro uint.ctz(self) => $$ctz(self);
+macro uint.clz(self) => $$clz(self);
+macro uint uint.fshl(hi, uint lo, uint shift) => $$fshl(hi, lo, shift);
+macro uint uint.fshr(hi, uint lo, uint shift) => $$fshr(hi, lo, shift);
+macro uint uint.rotl(self, uint shift) => $$fshl(self, self, shift);
+macro uint uint.rotr(self, uint shift) => $$fshr(self, self, shift);

-macro uint.popcount(uint i) => $$popcount(i);
-macro uint.ctz(uint i) => $$ctz(i);
-macro uint.clz(uint i) => $$clz(i);
-macro uint uint.fshl(uint hi, uint lo, uint shift) => $$fshl(hi, lo, shift);
-macro uint uint.fshr(uint hi, uint lo, uint shift) => $$fshr(hi, lo, shift);
-macro uint uint.rotl(uint i, uint shift) => $$fshl(i, i, shift);
-macro uint uint.rotr(uint i, uint shift) => $$fshr(i, i, shift);
+macro int.popcount(self) => $$popcount(self);
+macro int.ctz(self) => $$ctz(self);
+macro int.clz(self) => $$clz(self);
+macro int int.fshl(hi, int lo, int shift) => $$fshl(hi, lo, shift);
+macro int int.fshr(hi, int lo, int shift) => $$fshr(hi, lo, shift);
+macro int int.rotl(self, int shift) => $$fshl(self, self, shift);
+macro int int.rotr(self, int shift) => $$fshr(self, self, shift);

-macro int.popcount(int i) => $$popcount(i);
-macro int.ctz(int i) => $$ctz(i);
-macro int.clz(int i) => $$clz(i);
-macro int int.fshl(int hi, int lo, int shift) => $$fshl(hi, lo, shift);
-macro int int.fshr(int hi, int lo, int shift) => $$fshr(hi, lo, shift);
-macro int int.rotl(int i, int shift) => $$fshl(i, i, shift);
-macro int int.rotr(int i, int shift) => $$fshr(i, i, shift);
+macro ushort.popcount(self) => $$popcount(self);
+macro ushort.ctz(self) => $$ctz(self);
+macro ushort.clz(self) => $$clz(self);
+macro ushort ushort.fshl(hi, ushort lo, ushort shift) => $$fshl(hi, lo, shift);
+macro ushort ushort.fshr(hi, ushort lo, ushort shift) => $$fshr(hi, lo, shift);
+macro ushort ushort.rotl(self, ushort shift) => $$fshl(self, self, shift);
+macro ushort ushort.rotr(self, ushort shift) => $$fshr(self, self, shift);

-macro ushort.popcount(ushort i) => $$popcount(i);
-macro ushort.ctz(ushort i) => $$ctz(i);
-macro ushort.clz(ushort i) => $$clz(i);
-macro ushort ushort.fshl(ushort hi, ushort lo, ushort shift) => $$fshl(hi, lo, shift);
-macro ushort ushort.fshr(ushort hi, ushort lo, ushort shift) => $$fshr(hi, lo, shift);
-macro ushort ushort.rotl(ushort i, ushort shift) => $$fshl(i, i, shift);
-macro ushort ushort.rotr(ushort i, ushort shift) => $$fshr(i, i, shift);
+macro short.popcount(self) => $$popcount(self);
+macro short.ctz(self) => $$ctz(self);
+macro short.clz(self) => $$clz(self);
+macro short short.fshl(hi, short lo, short shift) => $$fshl(hi, lo, shift);
+macro short short.fshr(hi, short lo, short shift) => $$fshr(hi, lo, shift);
+macro short short.rotl(self, short shift) => $$fshl(self, self, shift);
+macro short short.rotr(self, short shift) => $$fshr(self, self, shift);

-macro short.popcount(short i) => $$popcount(i);
-macro short.ctz(short i) => $$ctz(i);
-macro short.clz(short i) => $$clz(i);
-macro short short.fshl(short hi, short lo, short shift) => $$fshl(hi, lo, shift);
-macro short short.fshr(short hi, short lo, short shift) => $$fshr(hi, lo, shift);
-macro short short.rotl(short i, short shift) => $$fshl(i, i, shift);
-macro short short.rotr(short i, short shift) => $$fshr(i, i, shift);
+macro char.popcount(self) => $$popcount(self);
+macro char.ctz(self) => $$ctz(self);
+macro char.clz(self) => $$clz(self);
+macro char char.fshl(hi, char lo, char shift) => $$fshl(hi, lo, shift);
+macro char char.fshr(hi, char lo, char shift) => $$fshr(hi, lo, shift);
+macro char char.rotl(self, char shift) => $$fshl(self, self, shift);
+macro char char.rotr(self, char shift) => $$fshr(self, self, shift);

-macro char.popcount(char i) => $$popcount(i);
-macro char.ctz(char i) => $$ctz(i);
-macro char.clz(char i) => $$clz(i);
-macro char char.fshl(char hi, char lo, char shift) => $$fshl(hi, lo, shift);
-macro char char.fshr(char hi, char lo, char shift) => $$fshr(hi, lo, shift);
-macro char char.rotl(char i, char shift) => $$fshl(i, i, shift);
-macro char char.rotr(char i, char shift) => $$fshr(i, i, shift);
+macro ichar.popcount(self) => $$popcount(self);
+macro ichar.ctz(self) => $$ctz(self);
+macro ichar.clz(self) => $$clz(self);
+macro ichar ichar.fshl(hi, ichar lo, ichar shift) => $$fshl(hi, lo, shift);
+macro ichar ichar.fshr(hi, ichar lo, ichar shift) => $$fshr(hi, lo, shift);
+macro ichar ichar.rotl(self, ichar shift) => $$fshl(self, self, shift);
+macro ichar ichar.rotr(self, ichar shift) => $$fshr(self, self, shift);

-macro ichar.popcount(ichar i) => $$popcount(i);
-macro ichar.ctz(ichar i) => $$ctz(i);
-macro ichar.clz(ichar i) => $$clz(i);
-macro ichar ichar.fshl(ichar hi, ichar lo, ichar shift) => $$fshl(hi, lo, shift);
-macro ichar ichar.fshr(ichar hi, ichar lo, ichar shift) => $$fshr(hi, lo, shift);
-macro ichar ichar.rotl(ichar i, ichar shift) => $$fshl(i, i, shift);
-macro ichar ichar.rotr(ichar i, ichar shift) => $$fshr(i, i, shift);
+macro ulong.popcount(self) => $$popcount(self);
+macro ulong.ctz(self) => $$ctz(self);
+macro ulong.clz(self) => $$clz(self);
+macro ulong ulong.fshl(hi, ulong lo, ulong shift) => $$fshl(hi, lo, shift);
+macro ulong ulong.fshr(hi, ulong lo, ulong shift) => $$fshr(hi, lo, shift);
+macro ulong ulong.rotl(self, ulong shift) => $$fshl(self, self, shift);
+macro ulong ulong.rotr(self, ulong shift) => $$fshr(self, self, shift);

-macro ulong.popcount(ulong i) => $$popcount(i);
-macro ulong.ctz(ulong i) => $$ctz(i);
-macro ulong.clz(ulong i) => $$clz(i);
-macro ulong ulong.fshl(ulong hi, ulong lo, ulong shift) => $$fshl(hi, lo, shift);
-macro ulong ulong.fshr(ulong hi, ulong lo, ulong shift) => $$fshr(hi, lo, shift);
-macro ulong ulong.rotl(ulong i, ulong shift) => $$fshl(i, i, shift);
-macro ulong ulong.rotr(ulong i, ulong shift) => $$fshr(i, i, shift);
+macro long.popcount(self) => $$popcount(self);
+macro long.ctz(self) => $$ctz(self);
+macro long.clz(self) => $$clz(self);
+macro long long.fshl(hi, long lo, long shift) => $$fshl(hi, lo, shift);
+macro long long.fshr(hi, long lo, long shift) => $$fshr(hi, lo, shift);
+macro long long.rotl(self, long shift) => $$fshl(self, self, shift);
+macro long long.rotr(self, long shift) => $$fshr(self, self, shift);

-macro long.popcount(long i) => $$popcount(i);
-macro long.ctz(long i) => $$ctz(i);
-macro long.clz(long i) => $$clz(i);
-macro long long.fshl(long hi, long lo, long shift) => $$fshl(hi, lo, shift);
-macro long long.fshr(long hi, long lo, long shift) => $$fshr(hi, lo, shift);
-macro long long.rotl(long i, long shift) => $$fshl(i, i, shift);
-macro long long.rotr(long i, long shift) => $$fshr(i, i, shift);
+macro uint128.popcount(self) => $$popcount(self);
+macro uint128.ctz(self) => $$ctz(self);
+macro uint128.clz(self) => $$clz(self);
+macro uint128 uint128.fshl(hi, uint128 lo, uint128 shift) => $$fshl(hi, lo, shift);
+macro uint128 uint128.fshr(hi, uint128 lo, uint128 shift) => $$fshr(hi, lo, shift);
+macro uint128 uint128.rotl(self, uint128 shift) => $$fshl(self, self, shift);
+macro uint128 uint128.rotr(self, uint128 shift) => $$fshr(self, self, shift);

-macro uint128.popcount(uint128 i) => $$popcount(i);
-macro uint128.ctz(uint128 i) => $$ctz(i);
-macro uint128.clz(uint128 i) => $$clz(i);
-macro uint128 uint128.fshl(uint128 hi, uint128 lo, uint128 shift) => $$fshl(hi, lo, shift);
-macro uint128 uint128.fshr(uint128 hi, uint128 lo, uint128 shift) => $$fshr(hi, lo, shift);
-macro uint128 uint128.rotl(uint128 i, uint128 shift) => $$fshl(i, i, shift);
-macro uint128 uint128.rotr(uint128 i, uint128 shift) => $$fshr(i, i, shift);
-
-macro int128.popcount(int128 i) => $$popcount(i);
-macro int128.ctz(int128 i) => $$ctz(i);
-macro int128.clz(int128 i) => $$clz(i);
-macro int128 int128.fshl(int128 hi, int128 lo, int128 shift) => $$fshl(hi, lo, shift);
-macro int128 int128.fshr(int128 hi, int128 lo, int128 shift) => $$fshr(hi, lo, shift);
-macro int128 int128.rotl(int128 i, int128 shift) => $$fshl(i, i, shift);
-macro int128 int128.rotr(int128 i, int128 shift) => $$fshr(i, i, shift);
+macro int128.popcount(self) => $$popcount(self);
+macro int128.ctz(self) => $$ctz(self);
+macro int128.clz(self) => $$clz(self);
+macro int128 int128.fshl(hi, int128 lo, int128 shift) => $$fshl(hi, lo, shift);
+macro int128 int128.fshr(hi, int128 lo, int128 shift) => $$fshr(hi, lo, shift);
+macro int128 int128.rotl(self, int128 shift) => $$fshl(self, self, shift);
+macro int128 int128.rotr(self, int128 shift) => $$fshr(self, self, shift);
--- a/lib/std/collections/bitset.c3
+++ b/lib/std/collections/bitset.c3
@@ -0,0 +1,160 @@
+/**
+ * @require SIZE > 0
+ **/
+module std::collections::bitset(<SIZE>);
+
+def Type = uint;
+
+const BITS = Type.sizeof * 8;
+const SZ = (SIZE + BITS - 1) / BITS;
+
+struct BitSet
+{
+	Type[SZ] data;
+}
+
+fn usz BitSet.cardinality(&self)
+{
+	usz n;
+	foreach (x : self.data)
+	{
+		n += x.popcount();
+	}
+	return n;
+}
+
+/**
+ * @require i < SIZE
+ **/
+fn void BitSet.set(&self, usz i)
+{
+	usz q = i / BITS;
+	usz r = i % BITS;
+	self.data[q] |= 1 << r;
+}
+
+/**
+ * @require i < SIZE
+ **/
+fn void BitSet.unset(&self, usz i)
+{
+	usz q = i / BITS;
+	usz r = i % BITS;
+	self.data[q] &= ~(1 << r);
+}
+
+/**
+ * @require i < SIZE
+ **/
+fn bool BitSet.get(&self, usz i) @operator([]) @inline
+{
+	usz q = i / BITS;
+	usz r = i % BITS;
+	return self.data[q] & (1 << r) != 0;
+}
+
+fn usz BitSet.len(&self) @operator(len) @inline
+{
+	return SZ * BITS;
+}
+
+/**
+ * @require i < SIZE
+ **/
+fn void BitSet.set_bool(&self, usz i, bool value) @operator([]=) @inline
+{
+	if (value) return self.set(i);
+	self.unset(i);
+}
+
+/**
+ * @require Type.kindof == UNSIGNED_INT
+ **/
+module std::collections::growablebitset(<Type>);
+import std::collections::list;
+
+const BITS = Type.sizeof * 8;
+
+def GrowableBitSetList = List(<Type>);
+
+struct GrowableBitSet
+{
+	GrowableBitSetList data;
+}
+
+/**
+ * @param initial_capacity
+ * @param [&inout] allocator "The allocator to use, defaults to the heap allocator"
+ **/
+fn GrowableBitSet* GrowableBitSet.init_new(&self, usz initial_capacity = 1, Allocator* allocator = mem::heap())
+{
+	self.data.init_new(initial_capacity, allocator);
+	return self;
+}
+
+fn GrowableBitSet* GrowableBitSet.init_temp(&self, usz initial_capacity = 1)
+{
+	return self.init_new(initial_capacity, mem::temp()) @inline;
+}
+
+fn void GrowableBitSet.free(&self)
+{
+	self.data.free();
+}
+
+fn usz GrowableBitSet.cardinality(&self)
+{
+	usz n;
+	foreach (x : self.data)
+	{
+		n += x.popcount();
+	}
+	return n;
+}
+
+fn void GrowableBitSet.set(&self, usz i)
+{
+	usz q = i / BITS;
+	usz r = i % BITS;
+	usz current_len = self.data.len();
+	if (q >= current_len)
+	{
+		usz n = q + 1;
+		self.data.reserve(n);
+		if (n - 1 >= current_len)
+		{
+			self.data.entries[current_len .. (n - 1)] = 0;
+		}
+		self.data.size = n;
+	}
+	self.data.set(q, self.data[q] | (1 << r));
+}
+
+fn void GrowableBitSet.unset(&self, usz i)
+{
+	usz q = i / BITS;
+	usz r = i % BITS;
+	if (q >= self.data.len()) return;
+	self.data.set(q, self.data[q] &~ (1 << r));
+}
+
+fn bool GrowableBitSet.get(&self, usz i) @operator([]) @inline
+{
+	usz q = i / BITS;
+	usz r = i % BITS;
+	if (q >= self.data.len()) return false;
+	return self.data[q] & (1 << r) != 0;
+}
+
+fn usz GrowableBitSet.len(&self) @operator(len)
+{
+	usz n = self.data.len() * BITS;
+	if (n > 0) n -= (usz)self.data[^1].clz();
+	return n;
+}
+
+fn void GrowableBitSet.set_bool(&self, usz i, bool value) @operator([]=) @inline
+{
+	if (value) return self.set(i);
+	self.unset(i);
+}
--- a/lib/std/collections/enummap.c3
+++ b/lib/std/collections/enummap.c3
@@ -1,18 +1,63 @@
-module std::collections::enummap<Enum, ValueType>;
+module std::collections::enummap(<Enum, ValueType>);

-struct EnumMap
+struct EnumMap (Printable)
 {
-    ValueType[Enum.len] values;
+	ValueType[Enum.len] values;
 }

-fn void EnumMap.init(EnumMap* this, ValueType init_value)
+fn void EnumMap.init(&self, ValueType init_value)
 {
-    foreach(&a : this.values)
-    {
-        *a = init_value;
-    }
+	foreach (&a : self.values)
+	{
+		*a = init_value;
+	}
 }

-fn uint EnumMap.len(EnumMap* this) @operator(len) => this.values.len;
-fn ValueType EnumMap.get(EnumMap* this, Enum key) @operator([]) => this.values[key.ordinal];
-fn void EnumMap.set(EnumMap* this, Enum key, ValueType value) @operator([]=) => this.values[key.ordinal] = value;
+fn usz! EnumMap.to_format(&self, Formatter* formatter) @dynamic
+{
+	usz n = formatter.print("{ ")!;
+	foreach (i, &value : self.values)
+	{
+		if (i != 0) formatter.print(", ")!;
+		n += formatter.printf("%s: %s", (Enum)i, *value)!;
+	}
+	n += formatter.print(" }")!;
+	return n;
+}
+
+fn String EnumMap.to_new_string(&self, Allocator* allocator = mem::heap()) @dynamic
+{
+	return string::new_format("%s", *self, .allocator = allocator);
+}
+
+fn String EnumMap.to_tstring(&self) @dynamic
+{
+	return string::tformat("%s", *self);
+}
+
+/**
+ * @return "The total size of this map, which is the same as the number of enum values"
+ * @pure
+ **/
+fn usz EnumMap.len(&self) @operator(len) @inline
+{
+	return self.values.len;
+}
+
+/**
+ * @return "Retrieve a value given the underlying enum, if there is no entry, then the zero value for the value is returned."
+ **/
+fn ValueType EnumMap.get(&self, Enum key) @operator([]) @inline
+{
+	return self.values[key.ordinal];
+}
+
+fn ValueType* EnumMap.get_ref(&self, Enum key) @operator(&[]) @inline
+{
+	return &self.values[key.ordinal];
+}
+
+fn void EnumMap.set(&self, Enum key, ValueType value) @operator([]=) @inline
+{
+	self.values[key.ordinal] = value;
+}
--- a/lib/std/collections/enumset.c3
+++ b/lib/std/collections/enumset.c3
@@ -1,145 +1,171 @@
 // Copyright (c) 2021 Christoffer Lerno. All rights reserved.
-// Use of this source code is governed by the MIT license
+// Use of self source code is governed by the MIT license
 // a copy of which can be found in the LICENSE_STDLIB file.

 /**
 * @require Enum.kindof == TypeKind.ENUM : "Only enums maybe be used with an enumset"
 **/
-module std::collections::enumset<Enum>;
+module std::collections::enumset(<Enum>);

+def EnumSetType = $typefrom(private::type_for_enum_elements(Enum.elements)) @private ;

-$switch
-$case (Enum.elements > 128):
-typedef EnumSetType @private = char[(Enum.elements + 7) / 8];
-const IS_CHAR_ARRAY = true;
-$case (Enum.elements > 64):
-typedef EnumSetType @private = uint128;
-const IS_CHAR_ARRAY = false;
-$case (Enum.elements > 32 || $$C_INT_SIZE > 32):
-typedef EnumSetType @private = ulong;
-const IS_CHAR_ARRAY = false;
-$case (Enum.elements > 16 || $$C_INT_SIZE > 16):
-typedef EnumSetType @private = uint;
-const IS_CHAR_ARRAY = false;
-$case (Enum.elements > 8 || $$C_INT_SIZE > 8):
-typedef EnumSetType @private = ushort;
-const IS_CHAR_ARRAY = false;
-$default:
-typedef EnumSetType @private = char;
-const IS_CHAR_ARRAY = false;
-$endswitch
+const IS_CHAR_ARRAY = Enum.elements > 128;
+distinct EnumSet (Printable) = EnumSetType;

-typedef EnumSet = distinct EnumSetType;
-
-fn void EnumSet.add(EnumSet* this, Enum v)
+fn void EnumSet.add(&self, Enum v)
 {
-$if (IS_CHAR_ARRAY)
-	(*this)[v / 8] |= (char)(1u << (v % 8));
-$else
-    *this = (EnumSet)((EnumSetType)*this | 1u << (EnumSetType)v);
-$endif
+	$if IS_CHAR_ARRAY:
+		(*self)[(usz)v / 8] |= (char)(1u << ((usz)v % 8));
+	$else
+		*self = (EnumSet)((EnumSetType)*self | 1u << (EnumSetType)v);
+	$endif
 }

-fn void EnumSet.clear(EnumSet* this)
+fn void EnumSet.clear(&self)
 {
-$if (IS_CHAR_ARRAY)
-	*this = {};
-$else
-    *this = 0;
-$endif
+	$if IS_CHAR_ARRAY:
+		*self = {};
+	$else
+		*self = 0;
+	$endif
 }

-fn bool EnumSet.remove(EnumSet* this, Enum v)
+fn bool EnumSet.remove(&self, Enum v)
 {
-$if (IS_CHAR_ARRAY)
-	if (!this.has(v) @inline) return false;
-	(*this)[v / 8] &= (char)~(1 << (v % 8));
-	return true;
-$else
-    EnumSetType old = (EnumSetType)*this;
-    EnumSetType new = old & ~(1u << (EnumSetType)v);
-    *this = (EnumSet)new;
-    return old != new;
-$endif
+	$if IS_CHAR_ARRAY:
+		if (!self.has(v) @inline) return false;
+		(*self)[(usz)v / 8] &= (char)~(1u << ((usz)v % 8));
+		return true;
+	$else
+		EnumSetType old = (EnumSetType)*self;
+		EnumSetType new = old & ~(1u << (EnumSetType)v);
+		*self = (EnumSet)new;
+		return old != new;
+	$endif
 }

-fn bool EnumSet.has(EnumSet* this, Enum v)
+fn bool EnumSet.has(&self, Enum v)
 {
-$if (IS_CHAR_ARRAY)
-	return (bool)(((*this)[v / 8] << (v % 8)) & 0x01);
-$else
-    return ((EnumSetType)*this & (1u << (EnumSetType)v)) != 0;
-$endif
+	$if IS_CHAR_ARRAY:
+		return (bool)(((*self)[(usz)v / 8] << ((usz)v % 8)) & 0x01);
+	$else
+		return ((EnumSetType)*self & (1u << (EnumSetType)v)) != 0;
+	$endif
 }

-fn void EnumSet.add_all(EnumSet* this, EnumSet s)
+fn void EnumSet.add_all(&self, EnumSet s)
 {
-$if (IS_CHAR_ARRAY)
-	foreach (i, c : s) (*this)[i] |= c;
-$else
-    *this = (EnumSet)((EnumSetType)*this | (EnumSetType)s);
-$endif
+	$if IS_CHAR_ARRAY:
+		foreach (i, c : s) (*self)[i] |= c;
+	$else
+		*self = (EnumSet)((EnumSetType)*self | (EnumSetType)s);
+	$endif
 }

-fn void EnumSet.retain_all(EnumSet* this, EnumSet s)
+fn void EnumSet.retain_all(&self, EnumSet s)
 {
-$if (IS_CHAR_ARRAY)
-	foreach (i, c : s) (*this)[i] &= c;
-$else
-    *this = (EnumSet)((EnumSetType)*this & (EnumSetType)s);
-$endif
+	$if IS_CHAR_ARRAY:
+		foreach (i, c : s) (*self)[i] &= c;
+	$else
+		*self = (EnumSet)((EnumSetType)*self & (EnumSetType)s);
+	$endif
 }

-fn void EnumSet.remove_all(EnumSet* this, EnumSet s)
+fn void EnumSet.remove_all(&self, EnumSet s)
 {
-$if (IS_CHAR_ARRAY)
-	foreach (i, c : s) (*this)[i] &= ~c;
-$else
-    *this = (EnumSet)((EnumSetType)*this & ~(EnumSetType)s);
-$endif
+	$if IS_CHAR_ARRAY:
+		foreach (i, c : s) (*self)[i] &= ~c;
+	$else
+		*self = (EnumSet)((EnumSetType)*self & ~(EnumSetType)s);
+	$endif
 }

-fn EnumSet EnumSet.and_of(EnumSet* this, EnumSet s)
+fn EnumSet EnumSet.and_of(&self, EnumSet s)
 {
-$if (IS_CHAR_ARRAY)
-	EnumSet copy = *this;
-	copy.retain_all(s);
-	return copy;
-$else
-    return (EnumSet)((EnumSetType)*this & (EnumSetType)s);
-$endif
+	$if IS_CHAR_ARRAY:
+		EnumSet copy = *self;
+		copy.retain_all(s);
+		return copy;
+	$else
+		return (EnumSet)((EnumSetType)*self & (EnumSetType)s);
+	$endif
 }

-fn EnumSet EnumSet.or_of(EnumSet* this, EnumSet s)
+fn EnumSet EnumSet.or_of(&self, EnumSet s)
 {
-$if (IS_CHAR_ARRAY)
-	EnumSet copy = *this;
-	copy.add_all(s);
-	return copy;
-$else
-    return (EnumSet)((EnumSetType)*this | (EnumSetType)s);
-$endif
+	$if IS_CHAR_ARRAY:
+		EnumSet copy = *self;
+		copy.add_all(s);
+		return copy;
+	$else
+		return (EnumSet)((EnumSetType)*self | (EnumSetType)s);
+	$endif
 }


-fn EnumSet EnumSet.diff_of(EnumSet* this, EnumSet s)
+fn EnumSet EnumSet.diff_of(&self, EnumSet s)
 {
-$if (IS_CHAR_ARRAY)
-	EnumSet copy = *this;
-	copy.remove_all(s);
-	return copy;
-$else
-    return (EnumSet)((EnumSetType)*this & ~(EnumSetType)s);
-$endif
+	$if IS_CHAR_ARRAY:
+		EnumSet copy = *self;
+		copy.remove_all(s);
+		return copy;
+	$else
+		return (EnumSet)((EnumSetType)*self & ~(EnumSetType)s);
+	$endif
 }

-fn EnumSet EnumSet.xor_of(EnumSet* this, EnumSet s)
+fn EnumSet EnumSet.xor_of(&self, EnumSet s)
 {
-$if (IS_CHAR_ARRAY)
-	EnumSet copy = *this;
-	foreach (i, c : s) copy[i] ^= c;
-	return copy;
-$else
-    return (EnumSet)((EnumSetType)*this ^ (EnumSetType)s);
-$endif
+	$if IS_CHAR_ARRAY:
+		EnumSet copy = *self;
+		foreach (i, c : s) copy[i] ^= c;
+		return copy;
+	$else
+		return (EnumSet)((EnumSetType)*self ^ (EnumSetType)s);
+	$endif
+}
+
+fn usz! EnumSet.to_format(&set, Formatter* formatter) @dynamic
+{
+	usz n = formatter.print("[")!;
+	bool found;
+	foreach (value : Enum.values)
+	{
+		if (!set.has(value)) continue;
+		if (found) n += formatter.print(", ")!;
+		found = true;
+		n += formatter.printf("%s", value)!;
+	}
+	n += formatter.print("]")!;
+	return n;
+}
+
+fn String EnumSet.to_new_string(&set, Allocator* allocator = mem::heap()) @dynamic
+{
+	return string::new_format("%s", *set, .allocator = allocator);
+}
+
+fn String EnumSet.to_tstring(&set) @dynamic
+{
+	return string::tformat("%s", *set);
+}
+
+module std::collections::enumset::private;
+
+macro typeid type_for_enum_elements(usz $elements)
+{
+	$switch
+		$case ($elements > 128):
+			return char[($elements + 7) / 8].typeid;
+		$case ($elements > 64):
+			return uint128.typeid;
+		$case ($elements > 32 || $$C_INT_SIZE > 32):
+			return ulong.typeid;
+		$case ($elements > 16 || $$C_INT_SIZE > 16):
+			return uint.typeid;
+		$case ($elements > 8 || $$C_INT_SIZE > 8):
+			return ushort.typeid;
+		$default:
+			return char.typeid;
+	$endswitch
 }
--- a/lib/std/collections/linkedlist.c3
+++ b/lib/std/collections/linkedlist.c3
@@ -1,312 +1,310 @@
 // Copyright (c) 2021 Christoffer Lerno. All rights reserved.
-// Use of this source code is governed by the MIT license
+// Use of self source code is governed by the MIT license
 // a copy of which can be found in the LICENSE_STDLIB file.
-module std::collections::linkedlist<Type>;
+module std::collections::linkedlist(<Type>);

 struct Node @private
 {
-    Node *next;
-    Node *prev;
-    Type value;
+	Node *next;
+	Node *prev;
+	Type value;
 }

 struct LinkedList
 {
-    Allocator *allocator;
-    usz size;
-    Node *_first;
-    Node *_last;
+	Allocator *allocator;
+	usz size;
+	Node *_first;
+	Node *_last;
 }

-fn void LinkedList.push(LinkedList* list, Type value)
+fn void LinkedList.push(&self, Type value)
 {
-    list.link_first(value);
+	self.link_first(value);
 }

-fn void LinkedList.push_last(LinkedList* list, Type value)
+fn void LinkedList.push_last(&self, Type value)
 {
-	list.link_last(value);
+	self.link_last(value);
 }

-fn void LinkedList.init(LinkedList* list, Allocator* using = mem::heap())
-{
-	*list = { .allocator = using };
-}
-
-fn void LinkedList.tinit(LinkedList* list) => list.init(mem::temp()) @inline;
-
 /**
- * @require list.allocator
+ * @param [&inout] allocator "The allocator to use, defaults to the heap allocator"
+ * @return "the initialized list"
 **/
-macro void LinkedList.@free_node(LinkedList &list, Node* node) @private
+fn LinkedList* LinkedList.init_new(&self, Allocator* allocator = mem::heap())
 {
-	list.allocator.free(node)!!;
-}
-macro Node* LinkedList.@alloc_node(LinkedList &list) @private
-{
-	if (!list.allocator) list.allocator = mem::heap();
-	return malloc(Node, .using = list.allocator);
+	*self = { .allocator = allocator };
+	return self;
 }

-fn void LinkedList.link_first(LinkedList* list, Type value) @private
+fn LinkedList* LinkedList.init_temp(&self)
 {
-    Node *first = list._first;
-    Node *new_node = list.@alloc_node();
-    *new_node = { .next = first, .value = value };
-    list._first = new_node;
-    if (!first)
-    {
-        list._last = new_node;
-    }
-    else
-    {
-        first.prev = new_node;
-    }
-    list.size++;
+	return self.init_new(mem::temp()) @inline;
 }

-fn void LinkedList.link_last(LinkedList* list, Type value) @private
-{
-    Node *last = list._last;
-    Node *new_node = list.@alloc_node();
-    *new_node = { .prev = last, .value = value };
-    list._last = new_node;
-    if (!last)
-    {
-        list._first = new_node;
-    }
-    else
-    {
-        last.next = new_node;
-    }
-    list.size++;
-}
-
-fn Type! peek(LinkedList* list) => list.first() @inline;
-fn Type! peek_last(LinkedList* list) => list.last() @inline;
-
-fn Type! LinkedList.first(LinkedList *list)
-{
-	if (!list._first) return IteratorResult.NO_MORE_ELEMENT!;
-	return list._first.value;
-}
-
-fn Type! LinkedList.last(LinkedList* list)
-{
-	if (!list._last) return IteratorResult.NO_MORE_ELEMENT!;
-	return list._last.value;
-}
-
-fn void LinkedList.free(LinkedList* list) => list.clear() @inline;
-
-fn void LinkedList.clear(LinkedList* list)
-{
-    for (Node* node = list._first; node != null;)
-    {
-        Node* next = node.next;
-        list.@free_node(node);
-        node = next;
-    }
-    list._first = null;
-    list._last = null;
-    list.size = 0;
-}
-
-fn usz LinkedList.len(LinkedList* list) @inline => list.size;
-
 /**
- * @require index < list.size
+ * @require self.allocator
 **/
-macro Node* LinkedList.node_at_index(LinkedList* list, usz index)
+macro void LinkedList.free_node(&self, Node* node) @private
 {
-	if (index * 2 >= list.size)
+	self.allocator.free(node);
+}
+macro Node* LinkedList.alloc_node(&self) @private
+{
+	if (!self.allocator) self.allocator = mem::heap();
+	return self.allocator.new(Node);
+}
+
+fn void LinkedList.link_first(&self, Type value) @private
+{
+	Node *first = self._first;
+	Node *new_node = self.alloc_node();
+	*new_node = { .next = first, .value = value };
+	self._first = new_node;
+	if (!first)
 	{
-	    Node* node = list._last;
-	    index = list.size - index - 1;
-        while (index--) node = node.prev;
-        return node;
+		self._last = new_node;
 	}
-    Node* node = list._first;
-    while (index--) node = node.next;
-    return node;
+	else
+	{
+		first.prev = new_node;
+	}
+	self.size++;
+}
+
+fn void LinkedList.link_last(&self, Type value) @private
+{
+	Node *last = self._last;
+	Node *new_node = self.alloc_node();
+	*new_node = { .prev = last, .value = value };
+	self._last = new_node;
+	if (!last)
+	{
+		self._first = new_node;
+	}
+	else
+	{
+		last.next = new_node;
+	}
+	self.size++;
+}
+
+fn Type! LinkedList.peek(&self) => self.first() @inline;
+fn Type! LinkedList.peek_last(&self) => self.last() @inline;
+
+fn Type! LinkedList.first(&self)
+{
+	if (!self._first) return IteratorResult.NO_MORE_ELEMENT?;
+	return self._first.value;
+}
+
+fn Type! LinkedList.last(&self)
+{
+	if (!self._last) return IteratorResult.NO_MORE_ELEMENT?;
+	return self._last.value;
+}
+
+fn void LinkedList.free(&self) => self.clear() @inline;
+
+fn void LinkedList.clear(&self)
+{
+	for (Node* node = self._first; node != null;)
+	{
+		Node* next = node.next;
+		self.free_node(node);
+		node = next;
+	}
+	self._first = null;
+	self._last = null;
+	self.size = 0;
+}
+
+fn usz LinkedList.len(&self) @inline => self.size;
+
+/**
+ * @require index < self.size
+ **/
+macro Node* LinkedList.node_at_index(&self, usz index)
+{
+	if (index * 2 >= self.size)
+	{
+		Node* node = self._last;
+		index = self.size - index - 1;
+		while (index--) node = node.prev;
+		return node;
+	}
+	Node* node = self._first;
+	while (index--) node = node.next;
+	return node;
 }
 /**
- * @require index < list.size
+ * @require index < self.size
 **/
-fn Type LinkedList.get(LinkedList* list, usz index)
+fn Type LinkedList.get(&self, usz index)
 {
-	return list.node_at_index(index).value;
+	return self.node_at_index(index).value;
 }

 /**
- * @require index < list.size
+ * @require index < self.size
 **/
-fn void LinkedList.set(LinkedList* list, usz index, Type element)
+fn void LinkedList.set(&self, usz index, Type element)
 {
-	list.node_at_index(index).value = element;
+	self.node_at_index(index).value = element;
 }

 /**
- * @require index < list.size
+ * @require index < self.size
 **/
-fn void LinkedList.remove(LinkedList* list, usz index)
+fn void LinkedList.remove(&self, usz index)
 {
-	list.unlink(list.node_at_index(index));
+	self.unlink(self.node_at_index(index));
 }

 /**
- * @require index <= list.size
+ * @require index <= self.size
 **/
-fn void LinkedList.insert(LinkedList* list, usz index, Type element)
+fn void LinkedList.insert(&self, usz index, Type element)
 {
 	switch (index)
 	{
 		case 0:
-			list.push(element);
-		case list.size:
-			list.push_last(element);
+			self.push(element);
+		case self.size:
+			self.push_last(element);
 		default:
-			list.link_before(list.node_at_index(index), element);
+			self.link_before(self.node_at_index(index), element);
 	}
 }
 /**
 * @require succ != null
 **/
-fn void LinkedList.link_before(LinkedList *list, Node *succ, Type value) @private
+fn void LinkedList.link_before(&self, Node *succ, Type value) @private
 {
-    Node* pred = succ.prev;
-    Node* new_node = malloc(Node);
-    *new_node = { .prev = pred, .next = succ, .value = value };
-    succ.prev = new_node;
-    if (!pred)
-    {
-        list._first = new_node;
-    }
-    else
-    {
-        pred.next = new_node;
-    }
-    list.size++;
+	Node* pred = succ.prev;
+	Node* new_node = self.alloc_node();
+	*new_node = { .prev = pred, .next = succ, .value = value };
+	succ.prev = new_node;
+	if (!pred)
+	{
+		self._first = new_node;
+	}
+	else
+	{
+		pred.next = new_node;
+	}
+	self.size++;
 }

 /**
- * @require list && list._first
+ * @require self._first
 **/
-fn void LinkedList.unlink_first(LinkedList* list) @private
+fn void LinkedList.unlink_first(&self) @private
 {
-	Node* f = list._first;
-    Node* next = f.next;
-    list.@free_node(f);
-    list._first = next;
-    if (!next)
-    {
-        list._last = null;
-    }
-    else
-    {
-        next.prev = null;
-    }
-    list.size--;
+	Node* f = self._first;
+	Node* next = f.next;
+	self.free_node(f);
+	self._first = next;
+	if (!next)
+	{
+		self._last = null;
+	}
+	else
+	{
+		next.prev = null;
+	}
+	self.size--;
 }

-fn bool LinkedList.remove_value(LinkedList* list, Type t)
+fn bool LinkedList.remove_value(&self, Type t)
 {
-    for (Node* node = list._first; node != null; node = node.next)
-    {
-        if (node.value == t)
-        {
-            list.unlink(node);
-            return true;
-        }
-    }
-    return false;
+	for (Node* node = self._first; node != null; node = node.next)
+	{
+		if (node.value == t)
+		{
+			self.unlink(node);
+			return true;
+		}
+	}
+	return false;
 }

-fn bool LinkedList.remove_last_value(LinkedList* list, Type t)
+fn bool LinkedList.remove_last_value(&self, Type t)
 {
-    for (Node* node = list._last; node != null; node = node.prev)
-    {
-        if (node.value == t)
-        {
-            list.unlink(node);
-            return true;
-        }
-    }
-    return false;
+	for (Node* node = self._last; node != null; node = node.prev)
+	{
+		if (node.value == t)
+		{
+			self.unlink(node);
+			return true;
+		}
+	}
+	return false;
+}
+
+fn Type! LinkedList.pop(&self)
+{
+	if (!self._first) return IteratorResult.NO_MORE_ELEMENT?;
+	defer self.unlink_first();
+	return self._first.value;
+}
+
+fn void! LinkedList.remove_last(&self)
+{
+	if (!self._first) return IteratorResult.NO_MORE_ELEMENT?;
+	self.unlink_last();
+}
+
+fn void! LinkedList.remove_first(&self)
+{
+	if (!self._first) return IteratorResult.NO_MORE_ELEMENT?;
+	self.unlink_first();
 }

 /**
- * @param [&inout] list
+ * @require self._last
 **/
-fn Type! LinkedList.pop(LinkedList* list)
+fn void LinkedList.unlink_last(&self) @inline @private
 {
-	if (!list._first) return IteratorResult.NO_MORE_ELEMENT!;
-	defer list.unlink_first();
-	return list._first.value;
+	Node* l = self._last;
+	Node* prev = l.prev;
+	self._last = prev;
+	self.free_node(l);
+	if (!prev)
+	{
+		self._first = null;
+	}
+	else
+	{
+		prev.next = null;
+	}
+	self.size--;
 }

 /**
- * @param [&inout] list
+ * @require x != null
 **/
-fn void! LinkedList.remove_last(LinkedList* list)
+fn void LinkedList.unlink(&self, Node* x) @private
 {
-	if (!list._first) return IteratorResult.NO_MORE_ELEMENT!;
-	list.unlink_last();
-}
-
-/**
- * @param [&inout] list
- **/
-fn void! LinkedList.remove_first(LinkedList* list)
-{
-	if (!list._first) return IteratorResult.NO_MORE_ELEMENT!;
-	list.unlink_first();
-}
-
-/**
- * @param [&inout] list
- * @require list._last
- **/
-fn void LinkedList.unlink_last(LinkedList *list) @inline @private
-{
-	Node* l = list._last;
-    Node* prev = l.prev;
-    list._last = prev;
-    list.@free_node(l);
-    if (!prev)
-    {
-        list._first = null;
-    }
-    else
-    {
-        prev.next = null;
-    }
-    list.size--;
-}
-
-/**
- * @require list != null, x != null
- **/
-fn void LinkedList.unlink(LinkedList* list, Node* x) @private
-{
-    Node* next = x.next;
-    Node* prev = x.prev;
-    if (!prev)
-    {
-        list._first = next;
-    }
-    else
-    {
-        prev.next = next;
-    }
-    if (!next)
-    {
-        list._last = prev;
-    }
-    else
-    {
-        next.prev = prev;
-    }
-    list.@free_node(x);
-    list.size--;
+	Node* next = x.next;
+	Node* prev = x.prev;
+	if (!prev)
+	{
+		self._first = next;
+	}
+	else
+	{
+		prev.next = next;
+	}
+	if (!next)
+	{
+		self._last = prev;
+	}
+	else
+	{
+		next.prev = prev;
+	}
+	self.free_node(x);
+	self.size--;
 }
--- a/lib/std/collections/list.c3
+++ b/lib/std/collections/list.c3
@@ -1,185 +1,489 @@
 // Copyright (c) 2021 Christoffer Lerno. All rights reserved.
-// Use of this source code is governed by the MIT license
+// Use of self source code is governed by the MIT license
 // a copy of which can be found in the LICENSE_STDLIB file.
-module std::collections::list<Type>;
+module std::collections::list(<Type>);
+import std::io;
 import std::math;

-struct List
+def ElementPredicate = fn bool(Type *type);
+def ElementTest = fn bool(Type *type, any* context);
+const ELEMENT_IS_EQUATABLE = types::is_equatable_type(Type);
+const ELEMENT_IS_POINTER = Type.kindof == POINTER;
+
+struct List (Printable)
 {
-    usz size;
-    usz capacity;
-    Allocator *allocator;
-    Type *entries;
+	usz size;
+	usz capacity;
+	Allocator *allocator;
+	Type *entries;
 }

 /**
- * @require using != null "A valid allocator must be provided"
+ * @param initial_capacity "The initial capacity to reserve"
+ * @param [&inout] allocator "The allocator to use, defaults to the heap allocator"
 **/
-fn void List.init(List* list, usz initial_capacity = 16, Allocator* using = mem::heap())
+fn List* List.init_new(&self, usz initial_capacity = 16, Allocator* allocator = mem::heap())
 {
-	list.allocator = using;
-	list.size = 0;
+	self.allocator = allocator;
+	self.size = 0;
 	if (initial_capacity > 0)
 	{
 		initial_capacity = math::next_power_of_2(initial_capacity);
-		list.entries = malloc_aligned(Type, initial_capacity, .alignment = Type[1].alignof, .using = using)!!;
+		self.entries = allocator.alloc_aligned(Type.sizeof * initial_capacity, .alignment = Type[1].alignof)!!;
 	}
 	else
 	{
-		list.entries = null;
+		self.entries = null;
 	}
-	list.capacity = initial_capacity;
-}
-
-fn void List.tinit(List* list, usz initial_capacity = 16)
-{
-	list.init(initial_capacity, mem::temp()) @inline;
-}
-
-fn void List.push(List* list, Type element) @inline
-{
-    list.append(element);
-}
-
-fn void List.append(List* list, Type element)
-{
-    list.ensure_capacity();
-    list.entries[list.size++] = element;
+	self.capacity = initial_capacity;
+	return self;
 }

 /**
- * @require list.size > 0
- */
-fn Type List.pop(List* list)
-{
-    return list.entries[--list.size];
-}
-
-fn void List.clear(List* list)
-{
-    list.size = 0;
-}
-
-/**
- * @require list.size > 0
- */
-fn Type List.pop_first(List* list)
-{
-    Type value = list.entries[0];
-    list.remove_at(0);
-    return value;
-}
-
-fn void List.remove_at(List* list, usz index)
-{
-    for (usz i = index + 1; i < list.size; i++)
-    {
-        list.entries[i - 1] = list.entries[i];
-    }
-    list.size--;
-}
-
-fn void List.push_front(List* list, Type type) @inline
-{
-    list.insert_at(0, type);
-}
-
-fn void List.insert_at(List* list, usz index, Type type)
-{
-    list.ensure_capacity();
-    for (usz i = list.size; i > index; i--)
-    {
-        list.entries[i] = list.entries[i - 1];
-    }
-    list.size++;
-    list.entries[index] = type;
-}
-
-/**
- * @require index < list.size
+ * Initialize the list using the temp allocator.
+ *
+ * @param initial_capacity "The initial capacity to reserve"
 **/
-fn void List.set_at(List* list, usz index, Type type)
+fn List* List.init_temp(&self, usz initial_capacity = 16)
 {
-    list.entries[index] = type;
+	return self.init_new(initial_capacity, mem::temp()) @inline;
 }

-fn void List.remove_last(List* list)
+/**
+ * @require self.size == 0 "The List must be empty"
+ **/
+fn void List.init_wrapping_array(&self, Type[] types, Allocator* allocator = mem::heap())
 {
-    list.size--;
+	self.allocator = allocator;
+	self.size = types.len;
+	self.capacity = types.len;
+	self.entries = types.ptr;
 }

-fn void List.remove_first(List* list)
+fn usz! List.to_format(&self, Formatter* formatter) @dynamic
 {
-    list.remove_at(0);
+	switch (self.size)
+	{
+		case 0:
+			return formatter.print("[]")!;
+		case 1:
+			return formatter.printf("[%s]", self.entries[0])!;
+		default:
+			usz n = formatter.print("[")!;
+			foreach (i, element : self.entries[:self.size])
+			{
+				if (i != 0) formatter.print(", ")!;
+				n += formatter.printf("%s", element)!;
+			}
+			n += formatter.print("]")!;
+			return n;
+	}
 }

-fn Type* List.first(List* list)
+fn String List.to_new_string(&self, Allocator* allocator = mem::heap()) @dynamic
 {
-    return list.size ? &list.entries[0] : null;
+	return string::new_format("%s", *self, .allocator = allocator);
 }

-fn Type* List.last(List* list)
+fn String List.to_tstring(&self)
 {
-    return list.size ? &list.entries[list.size - 1] : null;
+	return string::tformat("%s", *self);
 }

-fn bool List.is_empty(List* list)
+fn void List.push(&self, Type element) @inline
 {
-    return !list.size;
+	self.append(element);
 }

-fn usz List.len(List* list) @operator(len)
+fn void List.append(&self, Type element)
 {
-    return list.size;
+	self.ensure_capacity();
+	self.entries[self.size++] = element;
 }

-fn Type List.get(List* list, usz index)
+/**
+ * @require self.size > 0
+ **/
+fn Type List.pop(&self)
 {
-    return list.entries[index];
+	return self.entries[--self.size];
 }

-fn void List.free(List* list)
+fn void List.clear(&self)
 {
-	if (!list.allocator) return;
-    free_aligned(list.entries, .using = list.allocator);
-    list.capacity = 0;
-    list.size = 0;
-    list.entries = null;
+	self.size = 0;
 }

-fn void List.swap(List* list, usz i, usz j)
+/**
+ * @require self.size > 0
+ **/
+fn Type List.pop_first(&self)
 {
-	@swap(list.entries[i], list.entries[j]);
+	Type value = self.entries[0];
+	self.remove_at(0);
+	return value;
+}
+
+/**
+ * @require index < self.size
+ **/
+fn void List.remove_at(&self, usz index)
+{
+	for (usz i = index + 1; i < self.size; i++)
+	{
+		self.entries[i - 1] = self.entries[i];
+	}
+	self.size--;
+}
+
+fn void List.add_all(&self, List* other_list)
+{
+	if (!other_list.size) return;
+	self.reserve(other_list.size);
+	foreach (&value : other_list)
+	{
+		self.entries[self.size++] = *value;
+	}
+}
+
+
+fn Type[] List.to_new_array(&self, Allocator* allocator = mem::heap())
+{
+	if (!self.size) return Type[] {};
+	Type[] result = allocator.new_array(Type, self.size);
+	result[..] = self.entries[:self.size];
+	return result;
+}
+
+fn Type[] List.to_tarray(&self)
+{
+	return self.to_new_array(mem::temp());
+}
+
+/**
+ * Reverse the elements in a list.
+ **/
+fn void List.reverse(&self)
+{
+	if (self.size < 2) return;
+	usz half = self.size / 2U;
+	usz end = self.size - 1;
+	for (usz i = 0; i < half; i++)
+	{
+		@swap(self.entries[i], self.entries[end - i]);
+	}
+}
+
+fn Type[] List.array_view(&self)
+{
+	return self.entries[:self.size];
+}
+
+fn void List.add_array(&self, Type[] array)
+{
+	if (!array.len) return;
+	self.reserve(array.len);
+	foreach (&value : array)
+	{
+		self.entries[self.size++] = *value;
+	}
+}
+
+fn void List.push_front(&self, Type type) @inline
+{
+	self.insert_at(0, type);
+}
+
+/**
+ * @require index < self.size
+ **/
+fn void List.insert_at(&self, usz index, Type type)
+{
+	self.ensure_capacity();
+	for (usz i = self.size; i > index; i--)
+	{
+		self.entries[i] = self.entries[i - 1];
+	}
+	self.size++;
+	self.entries[index] = type;
+}
+
+/**
+ * @require index < self.size
+ **/
+fn void List.set_at(&self, usz index, Type type)
+{
+	self.entries[index] = type;
+}
+
+/**
+ * @require self.size > 0
+ **/
+fn void List.remove_last(&self)
+{
+	self.size--;
+}
+
+/**
+ * @require self.size > 0
+ **/
+fn void List.remove_first(&self)
+{
+	self.remove_at(0);
+}
+
+fn Type* List.first(&self)
+{
+	return self.size ? &self.entries[0] : null;
+}
+
+fn Type* List.last(&self)
+{
+	return self.size ? &self.entries[self.size - 1] : null;
+}
+
+fn bool List.is_empty(&self) @inline
+{
+	return !self.size;
+}
+
+fn usz List.len(&self) @operator(len) @inline
+{
+	return self.size;
+}
+
+fn Type List.get(&self, usz index) @inline
+{
+	return self.entries[index];
+}
+
+fn void List.free(&self)
+{
+	if (!self.allocator) return;
+	self.allocator.free_aligned(self.entries);
+	self.capacity = 0;
+	self.size = 0;
+	self.entries = null;
+}
+
+fn void List.swap(&self, usz i, usz j)
+{
+	@swap(self.entries[i], self.entries[j]);
+}
+
+/**
+ * @param filter "The function to determine if it should be removed or not"
+ * @return "the number of deleted elements"
+ **/
+fn usz List.remove_if(&self, ElementPredicate filter)
+{
+	return self._remove_if(filter, false);
+}
+
+/**
+ * @param selection "The function to determine if it should be kept or not"
+ * @return "the number of deleted elements"
+ **/
+fn usz List.retain_if(&self, ElementPredicate selection)
+{
+	return self._remove_if(selection, true);
+}
+
+macro usz List._remove_if(&self, ElementPredicate filter, bool $invert) @local
+{
+	usz size = self.size;
+	for (usz i = size, usz k = size; k > 0; k = i)
+	{
+		// Find last index of item to be deleted.
+		$if $invert:
+			while (i > 0 && !filter(&self.entries[i - 1])) i--;
+		$else
+			while (i > 0 && filter(&self.entries[i - 1])) i--;
+		$endif
+		// Remove the items from this index up to the one not to be deleted.
+		usz n = self.size - k;
+		self.entries[i:n] = self.entries[k:n];
+		self.size -= k - i;
+		// Find last index of item not to be deleted.
+		$if $invert:
+			while (i > 0 && filter(&self.entries[i - 1])) i--;
+		$else
+			while (i > 0 && !filter(&self.entries[i - 1])) i--;
+		$endif
+	}
+	return size - self.size;
+}
+
+fn usz List.remove_using_test(&self, ElementTest filter, any* context)
+{
+	return self._remove_using_test(filter, false, context);
+}
+
+fn usz List.retain_using_test(&self, ElementTest filter, any* context)
+{
+	return self._remove_using_test(filter, true, context);
+}
+
+macro usz List._remove_using_test(&self, ElementTest filter, bool $invert, ctx) @local
+{
+	usz size = self.size;
+	for (usz i = size, usz k = size; k > 0; k = i)
+	{
+		// Find last index of item to be deleted.
+		$if $invert:
+			while (i > 0 && !filter(&self.entries[i - 1], ctx)) i--;
+		$else
+			while (i > 0 && filter(&self.entries[i - 1], ctx)) i--;
+		$endif
+		// Remove the items from this index up to the one not to be deleted.
+		usz n = self.size - k;
+		self.entries[i:n] = self.entries[k:n];
+		self.size -= k - i;
+		// Find last index of item not to be deleted.
+		$if $invert:
+			while (i > 0 && filter(&self.entries[i - 1], ctx)) i--;
+		$else
+			while (i > 0 && !filter(&self.entries[i - 1], ctx)) i--;
+		$endif
+	}
+	return size - self.size;
 }

 /**
 * Reserve at least min_capacity
 **/
-fn void List.reserve(List* list, usz min_capacity)
+fn void List.reserve(&self, usz min_capacity)
 {
 	if (!min_capacity) return;
-	if (list.capacity >= min_capacity) return;
-	if (!list.allocator) list.allocator = mem::heap();
+	if (self.capacity >= min_capacity) return;
+	if (!self.allocator) self.allocator = mem::heap();
 	min_capacity = math::next_power_of_2(min_capacity);
-    list.entries = realloc_aligned(list.entries, Type.sizeof * min_capacity, .alignment = Type[1].alignof, .using = list.allocator) ?? null;
-	list.capacity = min_capacity;
+	self.entries = self.allocator.realloc_aligned(self.entries, Type.sizeof * min_capacity, .alignment = Type[1].alignof) ?? null;
+	self.capacity = min_capacity;
 }

-macro Type List.@item_at(List &list, usz index) @operator([])
+macro Type List.@item_at(&self, usz index) @operator([])
 {
-    return list.entries[index];
+	return self.entries[index];
 }

-fn Type* List.get_ref(List* list, usz index) @operator(&[]) @inline
+fn Type* List.get_ref(&self, usz index) @operator(&[]) @inline
 {
-    return &list.entries[index];
+	return &self.entries[index];
 }

-
-fn void List.ensure_capacity(List* list) @inline @private
+fn void List.set(&self, usz index, Type value) @operator([]=)
 {
-    if (list.capacity == list.size)
-    {
-        list.reserve(list.capacity ? 2 * list.capacity : 16);
-    }
+	self.entries[index] = value;
+}
+
+fn void List.ensure_capacity(&self, usz added = 1) @inline @private
+{
+	usz new_size = self.size + added;
+	if (self.capacity >= new_size) return;
+
+	assert(new_size < usz.max / 2U);
+	usz new_capacity = self.capacity ? 2U * self.capacity : 16U;
+	while (new_capacity < new_size) new_capacity *= 2U;
+	self.reserve(new_capacity);
+}
+
+// Functions for equatable types
+
+
+fn usz! List.index_of(&self, Type type) @if(ELEMENT_IS_EQUATABLE)
+{
+	foreach (i, v : self)
+	{
+		if (equals(v, type)) return i;
+	}
+	return SearchResult.MISSING?;
+}
+
+fn usz! List.rindex_of(&self, Type type) @if(ELEMENT_IS_EQUATABLE)
+{
+	foreach_r (i, v : self)
+	{
+		if (equals(v, type)) return i;
+	}
+	return SearchResult.MISSING?;
+}
+
+fn bool List.equals(&self, List other_list) @if(ELEMENT_IS_EQUATABLE)
+{
+	if (self.size != other_list.size) return false;
+	foreach (i, v : self)
+	{
+		if (!equals(v, other_list.entries[i])) return false;
+	}
+	return true;
+}
+
+/**
+ * Check for presence of a value in a list.
+ *
+ * @param [&in] self "the list to find elements in"
+ * @param value "The value to search for"
+ * @return "True if the value is found, false otherwise"
+ **/
+fn bool List.contains(&self, Type value) @if(ELEMENT_IS_EQUATABLE)
+{
+	foreach (i, v : self)
+	{
+		if (equals(v, value)) return true;
+	}
+	return false;
+}
+
+
+/**
+ * @param [&inout] self "The list to remove elements from"
+ * @param value "The value to remove"
+ * @return "the number of deleted elements."
+ **/
+fn usz List.remove(&self, Type value) @if(ELEMENT_IS_EQUATABLE)
+{
+	usz size = self.size;
+	for (usz i = size; i > 0; i--)
+	{
+		if (!equals(self.entries[i - 1], value)) continue;
+		for (usz j = i; j < size; j++)
+		{
+			self.entries[j - 1] = self.entries[j];
+		}
+		self.size--;
+	}
+	return size - self.size;
+}
+
+fn void List.remove_all(&self, List* other_list) @if(ELEMENT_IS_EQUATABLE)
+{
+	if (!other_list.size) return;
+	foreach (v : other_list) self.remove(v);
+}
+
+/**
+ * @param [&in] self
+ * @return "The number non-null values in the list"
+ **/
+fn usz List.compact_count(&self) @if(ELEMENT_IS_POINTER)
+{
+	usz vals = 0;
+	foreach (v : self) if (v) vals++;
+	return vals;
+}
+
+fn usz List.compact(&self) @if(ELEMENT_IS_POINTER)
+{
+	usz size = self.size;
+	for (usz i = size; i > 0; i--)
+	{
+		if (self.entries[i - 1]) continue;
+		for (usz j = i; j < size; j++)
+		{
+			self.entries[j - 1] = self.entries[j];
+		}
+		self.size--;
+	}
+	return size - self.size;
 }
--- a/lib/std/collections/map.c3
+++ b/lib/std/collections/map.c3
@@ -1,13 +1,14 @@
 // Copyright (c) 2023 Christoffer Lerno. All rights reserved.
 // Use of this source code is governed by the MIT license
 // a copy of which can be found in the LICENSE_STDLIB file.
-module std::collections::map<Key, Value>;
+module std::collections::map(<Key, Value>);
 import std::math;

 const uint DEFAULT_INITIAL_CAPACITY = 16;
 const uint MAXIMUM_CAPACITY = 1u << 31;
 const float DEFAULT_LOAD_FACTOR = 0.75;
-
+const VALUE_IS_EQUATABLE = Value.is_eq;
+const bool COPY_KEYS = types::implements_copy(Key);

 struct HashMap
 {
@@ -19,19 +20,20 @@ struct HashMap
 }

 /**
+ * @param [&inout] allocator "The allocator to use"
 * @require capacity > 0 "The capacity must be 1 or higher"
 * @require load_factor > 0.0 "The load factor must be higher than 0"
 * @require !map.allocator "Map was already initialized"
 * @require capacity < MAXIMUM_CAPACITY "Capacity cannot exceed maximum"
- * @require using != null "The allocator must be non-null"
 **/
-fn void HashMap.init(HashMap* map, uint capacity = DEFAULT_INITIAL_CAPACITY, float load_factor = DEFAULT_LOAD_FACTOR, Allocator* using = mem::heap())
+fn HashMap* HashMap.init_new(&map, uint capacity = DEFAULT_INITIAL_CAPACITY, float load_factor = DEFAULT_LOAD_FACTOR, Allocator* allocator = mem::heap())
 {
 	capacity = math::next_power_of_2(capacity);
-	map.allocator = using;
+	map.allocator = allocator;
 	map.load_factor = load_factor;
 	map.threshold = (uint)(capacity * load_factor);
-	map.table = calloc(Entry*, capacity, .using = using);
+	map.table = allocator.new_zero_array(Entry*, capacity);
+	return map;
 }

 /**
@@ -40,53 +42,77 @@ fn void HashMap.init(HashMap* map, uint capacity = DEFAULT_INITIAL_CAPACITY, flo
 * @require !map.allocator "Map was already initialized"
 * @require capacity < MAXIMUM_CAPACITY "Capacity cannot exceed maximum"
 **/
-fn void HashMap.tinit(HashMap* map, uint capacity = DEFAULT_INITIAL_CAPACITY, float load_factor = DEFAULT_LOAD_FACTOR)
+fn HashMap* HashMap.init_temp(&map, uint capacity = DEFAULT_INITIAL_CAPACITY, float load_factor = DEFAULT_LOAD_FACTOR)
 {
-	map.init(capacity, load_factor, mem::temp());
+	return map.init_new(capacity, load_factor, mem::temp());
 }

-fn void HashMap.init_from_map(HashMap* map, HashMap* other_map, Allocator* using = mem::heap())
+/**
+ * Has this hash map been initialized yet?
+ *
+ * @param [&in] map "The hash map we are testing"
+ * @return "Returns true if it has been initialized, false otherwise"
+ **/
+fn bool HashMap.is_initialized(&map)
 {
-	map.init(other_map.table.len, other_map.load_factor, using);
-	map.put_all_for_create(other_map);
+	return (bool)map.allocator;
 }

-fn void HashMap.tinit_from_map(HashMap* map, HashMap* other_map)
+/**
+ * @param [&inout] allocator "The allocator to use"
+ * @param [&in] other_map "The map to copy from."
+ **/
+fn HashMap* HashMap.init_new_from_map(&self, HashMap* other_map, Allocator* allocator = mem::heap())
 {
-	map.init_from_map(other_map, mem::temp()) @inline;
+	self.init_new(other_map.table.len, other_map.load_factor, allocator);
+	self.put_all_for_create(other_map);
+	return self;
 }

-fn bool HashMap.is_empty(HashMap* map) @inline
+/**
+ * @param [&in] other_map "The map to copy from."
+ **/
+fn HashMap* HashMap.init_temp_from_map(&map, HashMap* other_map)
+{
+	return map.init_new_from_map(other_map, mem::temp()) @inline;
+}
+
+fn bool HashMap.is_empty(&map) @inline
 {
 	return !map.count;
 }

-fn Value*! HashMap.get_ref(HashMap* map, Key key)
+fn usz HashMap.len(&map) @inline
 {
-	if (!map.count) return SearchResult.MISSING!;
+	return map.count;
+}
+
+fn Value*! HashMap.get_ref(&map, Key key)
+{
+	if (!map.count) return SearchResult.MISSING?;
 	uint hash = rehash(key.hash());
 	for (Entry *e = map.table[index_for(hash, map.table.len)]; e != null; e = e.next)
 	{
 		if (e.hash == hash && equals(key, e.key)) return &e.value;
 	}
-	return SearchResult.MISSING!;
+	return SearchResult.MISSING?;
 }

-fn Entry*! HashMap.get_entry(HashMap* map, Key key)
+fn Entry*! HashMap.get_entry(&map, Key key)
 {
-	if (!map.count) return SearchResult.MISSING!;
+	if (!map.count) return SearchResult.MISSING?;
 	uint hash = rehash(key.hash());
 	for (Entry *e = map.table[index_for(hash, map.table.len)]; e != null; e = e.next)
 	{
 		if (e.hash == hash && equals(key, e.key)) return e;
 	}
-	return SearchResult.MISSING!;
+	return SearchResult.MISSING?;
 }

 /**
 * Get the value or update and
 **/
-macro Value HashMap.@get_or_set(HashMap* map, Key key, Value #expr)
+macro Value HashMap.@get_or_set(&map, Key key, Value #expr)
 {
 	if (!map.count)
 	{
@@ -105,22 +131,22 @@ macro Value HashMap.@get_or_set(HashMap* map, Key key, Value #expr)
 	return val;
 }

-fn Value! HashMap.get(HashMap* map, Key key) @operator([])
+fn Value! HashMap.get(&map, Key key) @operator([])
 {
 	return *map.get_ref(key) @inline;
 }

-fn bool HashMap.has_key(HashMap* map, Key key)
+fn bool HashMap.has_key(&map, Key key)
 {
-	return try? map.get_ref(key);
+	return @ok(map.get_ref(key));
 }

-fn bool HashMap.set(HashMap* map, Key key, Value value) @operator([]=)
+fn bool HashMap.set(&map, Key key, Value value) @operator([]=)
 {
 	// If the map isn't initialized, use the defaults to initialize it.
 	if (!map.allocator)
 	{
-		map.init();
+		map.init_new();
 	}
 	uint hash = rehash(key.hash());
 	uint index = index_for(hash, map.table.len);
@@ -136,42 +162,49 @@ fn bool HashMap.set(HashMap* map, Key key, Value value) @operator([]=)
 	return false;
 }

-fn void! HashMap.remove(HashMap* map, Key key) @maydiscard
+fn void! HashMap.remove(&map, Key key) @maydiscard
 {
-	if (!map.remove_entry_for_key(key)) return SearchResult.MISSING!;
+	if (!map.remove_entry_for_key(key)) return SearchResult.MISSING?;
 }

-fn void HashMap.clear(HashMap* map)
+fn void HashMap.clear(&map)
 {
 	if (!map.count) return;
 	foreach (Entry** &entry_ref : map.table)
 	{
 		Entry* entry = *entry_ref;
 		if (!entry) continue;
-		map.free_internal(entry);
+		Entry *next = entry.next;
+		while (next)
+		{
+			Entry *to_delete = next;
+			next = next.next;
+			map.free_entry(to_delete);
+		}
+		map.free_entry(entry);
 		*entry_ref = null;
 	}
 	map.count = 0;
 }

-fn void HashMap.free(HashMap* map)
+fn void HashMap.free(&map)
 {
 	if (!map.allocator) return;
 	map.clear();
 	map.free_internal(map.table.ptr);
-	map.table = Entry*[] {};
+	map.table = {};
 }

-fn Key[] HashMap.key_tlist(HashMap* map)
+fn Key[] HashMap.key_tlist(&map)
 {
-	return map.key_list(mem::temp()) @inline;
+	return map.key_new_list(mem::temp()) @inline;
 }

-fn Key[] HashMap.key_list(HashMap* map, Allocator* using = mem::heap())
+fn Key[] HashMap.key_new_list(&map, Allocator* allocator = mem::heap())
 {
-	if (!map.count) return Key[] {};
+	if (!map.count) return {};

-	Key[] list = calloc(Key, map.count, .using = using);
+	Key[] list = allocator.new_array(Key, map.count);
 	usz index = 0;
 	foreach (Entry* entry : map.table)
 	{
@@ -184,15 +217,37 @@ fn Key[] HashMap.key_list(HashMap* map, Allocator* using = mem::heap())
 	return list;
 }

-fn Value[] HashMap.value_tlist(HashMap* map)
+macro HashMap.@each(map; @body(key, value))
 {
-	return map.value_list(mem::temp()) @inline;
+	map.@each_entry(; Entry* entry) {
+		@body(entry.key, entry.value);
+	};
 }

-fn Value[] HashMap.value_list(HashMap* map, Allocator* using = mem::heap())
+macro HashMap.@each_entry(map; @body(entry))
 {
-	if (!map.count) return Value[] {};
-	Value[] list = calloc(Value, map.count, .using = using);
+	if (map.count)
+	{
+		foreach (Entry* entry : map.table)
+		{
+			while (entry)
+			{
+				@body(entry);
+				entry = entry.next;
+			}
+		}
+	}
+}
+
+fn Value[] HashMap.value_tlist(&map)
+{
+	return map.value_new_list(mem::temp()) @inline;
+}
+
+fn Value[] HashMap.value_new_list(&map, Allocator* allocator = mem::heap())
+{
+	if (!map.count) return {};
+	Value[] list = allocator.new_array(Value, map.count);
 	usz index = 0;
 	foreach (Entry* entry : map.table)
 	{
@@ -205,8 +260,7 @@ fn Value[] HashMap.value_list(HashMap* map, Allocator* using = mem::heap())
 	return list;
 }

-$if (types::is_equatable(Value))
-fn bool HashMap.has_value(HashMap* map, Value v)
+fn bool HashMap.has_value(&map, Value v) @if(VALUE_IS_EQUATABLE)
 {
 	if (!map.count) return false;
 	foreach (Entry* entry : map.table)
@@ -219,22 +273,24 @@ fn bool HashMap.has_value(HashMap* map, Value v)
 	}
 	return false;
 }
-$endif

 // --- private methods

-fn void HashMap.add_entry(HashMap* map, uint hash, Key key, Value value, uint bucket_index) @private
+fn void HashMap.add_entry(&map, uint hash, Key key, Value value, uint bucket_index) @private
 {
-	Entry* entry = malloc(Entry, .using = map.allocator);
+	Entry* entry = map.allocator.new(Entry);
+	$if COPY_KEYS:
+	key = key.copy(map.allocator);
+	$endif
 	*entry = { .hash = hash, .key = key, .value = value, .next = map.table[bucket_index] };
 	map.table[bucket_index] = entry;
 	if (map.count++ >= map.threshold)
 	{
 		map.resize(map.table.len * 2);
-    }
+	}
 }

-fn void HashMap.resize(HashMap* map, uint new_capacity) @private
+fn void HashMap.resize(&map, uint new_capacity) @private
 {
 	Entry*[] old_table = map.table;
 	uint old_capacity = old_table.len;
@@ -243,7 +299,7 @@ fn void HashMap.resize(HashMap* map, uint new_capacity) @private
 		map.threshold = uint.max;
 		return;
 	}
-	Entry*[] new_table = calloc(Entry*, new_capacity, .using = map.allocator);
+	Entry*[] new_table = map.allocator.new_zero_array(Entry*, new_capacity);
 	map.transfer(new_table);
 	map.table = new_table;
 	map.free_internal(old_table.ptr);
@@ -252,8 +308,8 @@ fn void HashMap.resize(HashMap* map, uint new_capacity) @private

 fn uint rehash(uint hash) @inline @private
 {
-    hash ^= (hash >> 20) ^ (hash >> 12);
-    return hash ^ ((hash >> 7) ^ (hash >> 4));
+	hash ^= (hash >> 20) ^ (hash >> 12);
+	return hash ^ ((hash >> 7) ^ (hash >> 4));
 }

 macro uint index_for(uint hash, uint capacity) @private
@@ -261,39 +317,39 @@ macro uint index_for(uint hash, uint capacity) @private
 	return hash & (capacity - 1);
 }

-fn void HashMap.transfer(HashMap* map, Entry*[] new_table) @private
+fn void HashMap.transfer(&map, Entry*[] new_table) @private
 {
 	Entry*[] src = map.table;
-    uint new_capacity = new_table.len;
-    foreach (uint j, Entry *e : src)
-    {
-        if (!e) continue;
-        do
-        {
-            Entry* next = e.next;
-            uint i = index_for(e.hash, new_capacity);
-            e.next = new_table[i];
-            new_table[i] = e;
-            e = next;
-        }
-        while (e);
-    }
+	uint new_capacity = new_table.len;
+	foreach (uint j, Entry *e : src)
+	{
+		if (!e) continue;
+		do
+		{
+			Entry* next = e.next;
+			uint i = index_for(e.hash, new_capacity);
+			e.next = new_table[i];
+			new_table[i] = e;
+			e = next;
+		}
+		while (e);
+	}
 }

-fn void HashMap.put_all_for_create(HashMap* map, HashMap* other_map) @private
+fn void HashMap.put_all_for_create(&map, HashMap* other_map) @private
 {
 	if (!other_map.count) return;
-    foreach (Entry *e : other_map.table)
-    {
-        if (!e) continue;
-        map.put_for_create(e.key, e.value);
-    }
+	foreach (Entry *e : other_map.table)
+	{
+		if (!e) continue;
+		map.put_for_create(e.key, e.value);
+	}
 }

-fn void HashMap.put_for_create(HashMap* map, Key key, Value value) @private
+fn void HashMap.put_for_create(&map, Key key, Value value) @private
 {
-    uint hash = rehash(key.hash());
-    uint i = index_for(hash, map.table.len);
+	uint hash = rehash(key.hash());
+	uint i = index_for(hash, map.table.len);
 	for (Entry *e = map.table[i]; e != null; e = e.next)
 	{
 		if (e.hash == hash && equals(key, e.key))
@@ -305,12 +361,12 @@ fn void HashMap.put_for_create(HashMap* map, Key key, Value value) @private
 	map.create_entry(hash, key, value, i);
 }

-fn void HashMap.free_internal(HashMap* map, void* ptr) @inline @private
+fn void HashMap.free_internal(&map, void* ptr) @inline @private
 {
-	map.allocator.free(ptr)!!;
+	map.allocator.free(ptr);
 }

-fn bool HashMap.remove_entry_for_key(HashMap* map, Key key) @private
+fn bool HashMap.remove_entry_for_key(&map, Key key) @private
 {
 	uint hash = rehash(key.hash());
 	uint i = index_for(hash, map.table.len);
@@ -330,7 +386,7 @@ fn bool HashMap.remove_entry_for_key(HashMap* map, Key key) @private
 			{
 				prev.next = next;
 			}
-			map.free_internal(e);
+			map.free_entry(e);
 			return true;
 		}
 		prev = e;
@@ -339,19 +395,30 @@ fn bool HashMap.remove_entry_for_key(HashMap* map, Key key) @private
 	return false;
 }

-fn void HashMap.create_entry(HashMap* map, uint hash, Key key, Value value, int bucket_index) @private
+fn void HashMap.create_entry(&map, uint hash, Key key, Value value, int bucket_index) @private
 {
 	Entry *e = map.table[bucket_index];
-	Entry* entry = malloc(Entry, .using = map.allocator);
+	Entry* entry = map.allocator.new(Entry);
+	$if COPY_KEYS:
+	key = key.copy(map.allocator);
+	$endif
 	*entry = { .hash = hash, .key = key, .value = value, .next = map.table[bucket_index] };
 	map.table[bucket_index] = entry;
 	map.count++;
 }

+fn void HashMap.free_entry(&self, Entry *entry) @local
+{
+	$if COPY_KEYS:
+	self.allocator.free(entry.key);
+	$endif
+	self.free_internal(entry);
+}
+
 struct Entry
 {
 	uint hash;
 	Key key;
 	Value value;
 	Entry* next;
-}
+}
--- a/lib/std/collections/maybe.c3
+++ b/lib/std/collections/maybe.c3
@@ -0,0 +1,19 @@
+module std::collections::maybe(<Type>);
+
+struct Maybe
+{
+	Type value;
+	bool has_value;
+}
+
+fn Maybe value(Type val)
+{
+	return { .value = val, .has_value = true };
+}
+
+const Maybe EMPTY = { };
+
+macro Type! Maybe.get(self)
+{
+	return self.has_value ? self.value : SearchResult.MISSING?;
+}
--- a/lib/std/collections/object.c3
+++ b/lib/std/collections/object.c3
@@ -10,7 +10,7 @@ const Object TRUE_OBJECT = { .b = true, .type = bool.typeid };
 const Object FALSE_OBJECT = { .b = false, .type = bool.typeid };
 const Object NULL_OBJECT = { .type = void*.typeid };

-struct Object
+struct Object (Printable)
 {
 	typeid type;
 	Allocator* allocator;
@@ -26,64 +26,62 @@ struct Object
 	}
 }

-static initialize
-{
-	io::formatter_register_type(Object);
-}

-fn void! Object.to_format(Object* o, Formatter* formatter)
+fn usz! Object.to_format(&self, Formatter* formatter) @dynamic
 {
-	switch (o.type)
+	switch (self.type)
 	{
 		case void:
-			formatter.printf("{}")?;
+			return formatter.printf("{}")!;
 		case void*:
-			formatter.printf("null")?;
+			return formatter.printf("null")!;
 		case String:
-			formatter.printf(`"%s"`, o.s)?;
+			return formatter.printf(`"%s"`, self.s)!;
 		case bool:
-			formatter.printf(o.b ? "true" : "false")?;
+			return formatter.printf(self.b ? "true" : "false")!;
 		case ObjectInternalList:
-			formatter.printf("[")?;
-			foreach (i, ol : o.array)
+			usz n = formatter.printf("[")!;
+			foreach (i, ol : self.array)
 			{
-				formatter.printf(i == 0 ? " " : ", ")?;
-				ol.to_format(formatter)?;
+				if (i > 0) n += formatter.printf(",")!;
+				n += ol.to_format(formatter)!;
 			}
-			formatter.printf(" ]")?;
+			n += formatter.printf("]")!;
+			return n;
 		case ObjectInternalMap:
-			formatter.printf("{")?;
+			usz n = formatter.printf("{")!;
 			@pool()
 			{
-				foreach (i, key : o.map.key_tlist())
+				foreach (i, key : self.map.key_tlist())
 				{
-					formatter.printf(i == 0 ? " " : ", ")?;
-					formatter.printf(`"%s": `, key)?;
-					o.map.get(key).to_format(formatter)?;
+					if (i > 0) n += formatter.printf(",")!;
+					n += formatter.printf(`"%s":`, key)!;
+					n += self.map.get(key).to_format(formatter)!;
 				}
 			};
-			formatter.printf(" }")?;
+			n += formatter.printf("}")!;
+			return n;
 		default:
-			switch (o.type.kindof)
+			switch (self.type.kindof)
 			{
 				case SIGNED_INT:
-					formatter.printf("%d", o.i)?;
+					return formatter.printf("%d", self.i)!;
 				case UNSIGNED_INT:
-					formatter.printf("%d", (uint128)o.i)?;
+					return formatter.printf("%d", (uint128)self.i)!;
 				case FLOAT:
-					formatter.printf("%d", o.f)?;
+					return formatter.printf("%d", self.f)!;
 				case ENUM:
-					formatter.printf("%d", o.i)?;
+					return formatter.printf("%d", self.i)!;
 				default:
-					formatter.printf("<>")?;
+					return formatter.printf("<>")!;
 			}
 	}
 }

-fn Object* new_obj(Allocator* using = mem::heap())
+fn Object* new_obj(Allocator* allocator)
 {
-	Object* o = malloc(Object, .using = using);
-	*o = { .allocator = using, .type = void.typeid };
+	Object* o = allocator.new(Object);
+	*o = { .allocator = allocator, .type = void.typeid };
 	return o;
 }

@@ -92,31 +90,31 @@ fn Object* new_null()
 	return &NULL_OBJECT;
 }

-fn Object* new_int(int128 i, Allocator* using = mem::heap())
+fn Object* new_int(int128 i, Allocator* allocator)
 {
-	Object* o = malloc(Object, .using = using);
-	*o = { .i = i, .allocator = using, .type = int128.typeid };
+	Object* o = allocator.new(Object);
+	*o = { .i = i, .allocator = allocator, .type = int128.typeid };
 	return o;
 }

-macro Object* new_enum(e, Allocator* using = mem::heap())
+macro Object* new_enum(e, Allocator* allocator)
 {
-	Object* o = malloc(Object, .using = using);
-	*o = { .i = (int128)e, .allocator = using, .type = $typeof(e).typeid };
+	Object* o = allocator.new(Object);
+	*o = { .i = (int128)e, .allocator = allocator, .type = @typeid(e) };
 	return o;
 }

-fn Object* new_float(double f, Allocator* using = mem::current_allocator())
+fn Object* new_float(double f, Allocator* allocator)
 {
-	Object* o = malloc(Object, .using = using);
-	*o = { .f = f, .allocator = using, .type = double.typeid };
+	Object* o = allocator.new(Object);
+	*o = { .f = f, .allocator = allocator, .type = double.typeid };
 	return o;
 }

-fn Object* new_string(String s, Allocator* using = mem::heap())
+fn Object* new_string(String s, Allocator* allocator)
 {
-	Object* o = malloc(Object, .using = using);
-	*o = { .s = s.copy(using), .allocator = using, .type = String.typeid };
+	Object* o = allocator.new(Object);
+	*o = { .s = s.copy(allocator), .allocator = allocator, .type = String.typeid };
 	return o;
 }

@@ -126,187 +124,190 @@ fn Object* new_bool(bool b)
 	return b ? &TRUE_OBJECT : &FALSE_OBJECT;
 }

-/**
- * @param [&inout] o
- **/
-fn void Object.free(Object* o)
+fn void Object.free(&self)
 {
-	switch (o.type)
+	switch (self.type)
 	{
 		case void:
 			break;
 		case String:
-			free(o.s, .using = o.allocator);
+			self.allocator.free(self.s);
 		case ObjectInternalList:
-			foreach (ol : o.array)
+			foreach (ol : self.array)
 			{
 				ol.free();
 			}
-			o.array.free();
+			self.array.free();
 		case ObjectInternalMap:
-			@pool()
-			{
-				foreach (key : o.map.key_tlist())
-				{
-					o.map.get(key).free();
-					free(key, .using = o.allocator);
-				}
-				o.map.free();
+			self.map.@each_entry(; ObjectInternalMapEntry* entry) {
+				self.allocator.free(entry.key);
+				entry.value.free();
 			};
 		default:
 			break;
 	}
-	if (o.allocator) free(o, .using = o.allocator);
+	if (self.allocator) self.allocator.free(self);
 }

-fn bool Object.is_null(Object* this) @inline => this == &NULL_OBJECT;
-fn bool Object.is_empty(Object* this) @inline => this.type == void.typeid;
-fn bool Object.is_map(Object* this) @inline => this.type == ObjectInternalMap.typeid;
-fn bool Object.is_array(Object* this) @inline => this.type == ObjectInternalList.typeid;
-fn bool Object.is_bool(Object* this) @inline => this.type == bool.typeid;
-fn bool Object.is_string(Object* this) @inline => this.type == String.typeid;
-fn bool Object.is_float(Object* this) @inline => this.type == double.typeid;
-fn bool Object.is_int(Object* this) @inline => this.type == int128.typeid;
-fn bool Object.is_keyable(Object* this) => this.is_empty() || this.is_map();
-fn bool Object.is_indexable(Object* this) => this.is_empty() || this.is_array();
+fn bool Object.is_null(&self) @inline => self == &NULL_OBJECT;
+fn bool Object.is_empty(&self) @inline => self.type == void.typeid;
+fn bool Object.is_map(&self) @inline => self.type == ObjectInternalMap.typeid;
+fn bool Object.is_array(&self) @inline => self.type == ObjectInternalList.typeid;
+fn bool Object.is_bool(&self) @inline => self.type == bool.typeid;
+fn bool Object.is_string(&self) @inline => self.type == String.typeid;
+fn bool Object.is_float(&self) @inline => self.type == double.typeid;
+fn bool Object.is_int(&self) @inline => self.type == int128.typeid;
+fn bool Object.is_keyable(&self) => self.is_empty() || self.is_map();
+fn bool Object.is_indexable(&self) => self.is_empty() || self.is_array();

 /**
- * @require o.is_keyable()
+ * @require self.is_keyable()
 **/
-fn void Object.init_map_if_needed(Object* o) @private
+fn void Object.init_map_if_needed(&self) @private
 {
-	if (o.is_empty())
+	if (self.is_empty())
 	{
-		o.type = ObjectInternalMap.typeid;
-		o.map.init(.using = o.allocator);
+		self.type = ObjectInternalMap.typeid;
+		self.map.init_new(.allocator = self.allocator);
 	}
 }

 /**
- * @require o.is_indexable()
+ * @require self.is_indexable()
 **/
-fn void Object.init_array_if_needed(Object* o) @private
+fn void Object.init_array_if_needed(&self) @private
 {
-	if (o.is_empty())
+	if (self.is_empty())
 	{
-		o.type = ObjectInternalList.typeid;
-		o.array.init(.using = o.allocator);
+		self.type = ObjectInternalList.typeid;
+		self.array.init_new(.allocator = self.allocator);
 	}
 }

 /**
- * @require o.is_keyable()
+ * @require self.is_keyable()
 **/
-fn void Object.set_object(Object* o, String key, Object* new_object) @private
+fn void Object.set_object(&self, String key, Object* new_object) @private
 {
-	o.init_map_if_needed();
-	ObjectInternalMapEntry*! entry = o.map.get_entry(key);
+	self.init_map_if_needed();
+	ObjectInternalMapEntry*! entry = self.map.get_entry(key);
 	defer
 	{
-		(void)free(entry.key, .using = o.allocator);
-		entry.value.free();
+		(void)self.allocator.free(entry.key);
+		(void)entry.value.free();
 	}
-	o.map.set(key.copy(o.map.allocator), new_object);
+	self.map.set(key.copy(self.map.allocator), new_object);
 }

-macro Object* object_from_value(value) @private
+macro Object* Object.object_from_value(&self, value) @private
 {
 	var $Type = $typeof(value);

-$switch
-	$case types::is_int($Type):
-		return new_int(value);
-	$case types::is_float($Type):
-		return new_float(value);
-	$case $Type.typeid == String.typeid:
-		return new_string(value);
-	$case $Type.typeid == bool.typeid:
-		return new_bool(value);
-	$case $Type.typeid == Object*.typeid:
-		return value;
-	$case $Type.typeid == void*.typeid:
-		assert(value == null);
-		return &NULL_OBJECT;
-	$case $checks(String s = value):
-		return new_string(value);
-	$default:
-		$assert(false, "Unsupported object type.");
-$endswitch
+	$switch
+		$case types::is_int($Type):
+			return new_int(value, self.allocator);
+		$case types::is_float($Type):
+			return new_float(value, self.allocator);
+		$case $Type.typeid == String.typeid:
+			return new_string(value, self.allocator);
+		$case $Type.typeid == bool.typeid:
+			return new_bool(value);
+		$case $Type.typeid == Object*.typeid:
+			return value;
+		$case $Type.typeid == void*.typeid:
+			if (value != null) return CastResult.TYPE_MISMATCH?;
+			return &NULL_OBJECT;
+		$case $assignable(value, String):
+			return new_string(value, self.allocator);
+		$default:
+			$error "Unsupported object type.";
+	$endswitch

 }

-macro Object* Object.set(Object* o, String key, value)
+macro Object* Object.set(&self, String key, value)
 {
-	Object* val = object_from_value(value);
-	o.set_object(key, val);
+	Object* val = self.object_from_value(value);
+	self.set_object(key, val);
 	return val;
 }

 /**
- * @require o.is_indexable()
+ * @require self.is_indexable()
 **/
-macro Object* Object.set_at(Object* o, usz index, String key, value)
+macro Object* Object.set_at(&self, usz index, String key, value)
 {
-	Object* val = object_from_value(value);
-	o.set_object_at(key, index, val);
+	Object* val = self.object_from_value(value);
+	self.set_object_at(key, index, val);
 	return val;
 }

 /**
- * @require o.is_indexable()
+ * @require self.is_indexable()
 * @ensure return != null
 **/
-macro Object* Object.append(Object* o, value)
+macro Object* Object.append(&self, value)
 {
-	Object* val = object_from_value(value);
-	o.append_object(val);
+	Object* val = self.object_from_value(value);
+	self.append_object(val);
 	return val;
 }

 /**
- * @require o.is_keyable()
+ * @require self.is_keyable()
 **/
-fn Object*! Object.get(Object* o, String key) => o.is_empty() ? SearchResult.MISSING! : o.map.get(key);
+fn Object*! Object.get(&self, String key) => self.is_empty() ? SearchResult.MISSING? : self.map.get(key);


-fn bool Object.has_key(Object* o, String key) => o.is_map() && o.map.has_key(key);
+fn bool Object.has_key(&self, String key) => self.is_map() && self.map.has_key(key);

 /**
- * @require o.is_indexable()
+ * @require self.is_indexable()
 **/
-fn Object* Object.get_at(Object* o, usz index)
+fn Object* Object.get_at(&self, usz index)
 {
-	return o.array.get(index);
+	return self.array.get(index);
 }

 /**
- * @require o.is_indexable()
+ * @require self.is_indexable()
 **/
-fn void Object.append_object(Object* o, Object* to_append)
+fn usz Object.get_len(&self)
 {
-	o.init_array_if_needed();
-	o.array.append(to_append);
+	return self.array.len();
 }

 /**
- * @require o.is_indexable()
+ * @require self.is_indexable()
 **/
-fn void Object.set_object_at(Object* o, usz index, Object* to_set)
+fn void Object.append_object(&self, Object* to_append)
 {
-	o.init_array_if_needed();
-	while (o.array.len() < index)
+	self.init_array_if_needed();
+	self.array.append(to_append);
+}
+
+/**
+ * @require self.is_indexable()
+ **/
+fn void Object.set_object_at(&self, usz index, Object* to_set)
+{
+	self.init_array_if_needed();
+	while (self.array.len() < index)
 	{
-		o.array.append(&NULL_OBJECT);
+		self.array.append(&NULL_OBJECT);
 	}
-	if (o.array.len() == index)
+	if (self.array.len() == index)
 	{
-		o.array.append(to_set);
+		self.array.append(to_set);
 		return;
 	}
-	o.array.get(index).free();
-	o.array.set_at(index, to_set);
+	self.array.get(index).free();
+	self.array.set_at(index, to_set);
 }

+/**
+ * @require $Type.kindof.is_int() "Expected an integer type."
+ **/
 macro get_integer_value(Object* value, $Type)
 {
 	if (value.is_float())
@@ -315,123 +316,126 @@ macro get_integer_value(Object* value, $Type)
 	}
 	if (value.is_string())
 	{
-		$if ($Type.kindof == TypeKind.SIGNED_INT)
-			return ($Type)str::to_int128(value.s);
+		$if $Type.kindof == TypeKind.SIGNED_INT:
+			return ($Type)value.s.to_int128();
 		$else
-			return ($Type)str::to_uint128(value.s);
+			return ($Type)value.s.to_uint128();
 		$endif
 	}
-	if (!value.is_int()) return NumberConversion.MALFORMED_INTEGER!;
+	if (!value.is_int()) return NumberConversion.MALFORMED_INTEGER?;
 	return ($Type)value.i;
 }

+
 /**
- * @require o.is_indexable()
+ * @require self.is_indexable()
+ * @require $Type.kindof.is_int() : "Expected an integer type"
 **/
-macro Object.get_integer_at(Object* o, $Type, usz index) @private
+macro Object.get_integer_at(&self, $Type, usz index) @private
 {
-	return get_integer_value(o.get_at(index), $Type);
+	return get_integer_value(self.get_at(index), $Type);
 }

 /**
- * @require o.is_keyable()
+ * @require self.is_keyable()
+ * @require $Type.kindof.is_int() : "Expected an integer type"
 **/
-macro Object.get_integer(Object* o, $Type, String key) @private
+macro Object.get_integer(&self, $Type, String key) @private
 {
-	return get_integer_value(o.get(key), $Type);
+	return get_integer_value(self.get(key), $Type);
 }

-fn ichar! Object.get_ichar(Object* o, String key) => o.get_integer(ichar, key);
-fn short! Object.get_short(Object* o, String key) => o.get_integer(short, key);
-fn int! Object.get_int(Object* o, String key) => o.get_integer(int, key);
-fn long! Object.get_long(Object* o, String key) => o.get_integer(long, key);
-fn int128! Object.get_int128(Object* o, String key) => o.get_integer(int128, key);
+fn ichar! Object.get_ichar(&self, String key) => self.get_integer(ichar, key);
+fn short! Object.get_short(&self, String key) => self.get_integer(short, key);
+fn int! Object.get_int(&self, String key) => self.get_integer(int, key);
+fn long! Object.get_long(&self, String key) => self.get_integer(long, key);
+fn int128! Object.get_int128(&self, String key) => self.get_integer(int128, key);

-fn ichar! Object.get_ichar_at(Object* o, usz index) => o.get_integer_at(ichar, index);
-fn short! Object.get_short_at(Object* o, usz index) => o.get_integer_at(short, index);
-fn int! Object.get_int_at(Object* o, usz index) => o.get_integer_at(int, index);
-fn long! Object.get_long_at(Object* o, usz index) => o.get_integer_at(long, index);
-fn int128! Object.get_int128_at(Object* o, usz index) => o.get_integer_at(int128, index);
+fn ichar! Object.get_ichar_at(&self, usz index) => self.get_integer_at(ichar, index);
+fn short! Object.get_short_at(&self, usz index) => self.get_integer_at(short, index);
+fn int! Object.get_int_at(&self, usz index) => self.get_integer_at(int, index);
+fn long! Object.get_long_at(&self, usz index) => self.get_integer_at(long, index);
+fn int128! Object.get_int128_at(&self, usz index) => self.get_integer_at(int128, index);

-fn char! Object.get_char(Object* o, String key) => o.get_integer(ichar, key);
-fn short! Object.get_ushort(Object* o, String key) => o.get_integer(ushort, key);
-fn uint! Object.get_uint(Object* o, String key) => o.get_integer(uint, key);
-fn ulong! Object.get_ulong(Object* o, String key) => o.get_integer(ulong, key);
-fn uint128! Object.get_uint128(Object* o, String key) => o.get_integer(uint128, key);
+fn char! Object.get_char(&self, String key) => self.get_integer(ichar, key);
+fn short! Object.get_ushort(&self, String key) => self.get_integer(ushort, key);
+fn uint! Object.get_uint(&self, String key) => self.get_integer(uint, key);
+fn ulong! Object.get_ulong(&self, String key) => self.get_integer(ulong, key);
+fn uint128! Object.get_uint128(&self, String key) => self.get_integer(uint128, key);

-fn char! Object.get_char_at(Object* o, usz index) => o.get_integer_at(char, index);
-fn ushort! Object.get_ushort_at(Object* o, usz index) => o.get_integer_at(ushort, index);
-fn uint! Object.get_uint_at(Object* o, usz index) => o.get_integer_at(uint, index);
-fn ulong! Object.get_ulong_at(Object* o, usz index) => o.get_integer_at(ulong, index);
-fn uint128! Object.get_uint128_at(Object* o, usz index) => o.get_integer_at(uint128, index);
+fn char! Object.get_char_at(&self, usz index) => self.get_integer_at(char, index);
+fn ushort! Object.get_ushort_at(&self, usz index) => self.get_integer_at(ushort, index);
+fn uint! Object.get_uint_at(&self, usz index) => self.get_integer_at(uint, index);
+fn ulong! Object.get_ulong_at(&self, usz index) => self.get_integer_at(ulong, index);
+fn uint128! Object.get_uint128_at(&self, usz index) => self.get_integer_at(uint128, index);

 /**
- * @require o.is_keyable()
+ * @require self.is_keyable()
 **/
-fn String! Object.get_string(Object* o, String key)
+fn String! Object.get_string(&self, String key)
 {
-	Object* value = o.get(key)?;
-	assert(value.is_string());
+	Object* value = self.get(key)!;
+	if (!value.is_string()) return CastResult.TYPE_MISMATCH?;
 	return value.s;
 }

 /**
- * @require o.is_indexable()
+ * @require self.is_indexable()
 **/
-fn String Object.get_string_at(Object* o, usz index)
+fn String! Object.get_string_at(&self, usz index)
 {
-	Object* value = o.get_at(index);
-	assert(value.is_string());
+	Object* value = self.get_at(index);
+	if (!value.is_string()) return CastResult.TYPE_MISMATCH?;
 	return value.s;
 }

 /**
- * @require o.is_keyable()
+ * @require self.is_keyable()
 **/
-macro String! Object.get_enum(Object* o, $EnumType, String key)
+macro String! Object.get_enum(&self, $EnumType, String key)
 {
-	Object value = o.get(key)?;
-	assert($EnumType.typeid == value.type);
+	Object value = self.get(key)!;
+	if ($EnumType.typeid != value.type) return CastResult.TYPE_MISMATCH?;
 	return ($EnumType)value.i;
 }

 /**
- * @require o.is_indexable()
+ * @require self.is_indexable()
 **/
-macro String Object.get_enum_at(Object* o, $EnumType, usz index)
+macro String! Object.get_enum_at(&self, $EnumType, usz index)
 {
-	Object value = o.get_at(index);
-	assert($EnumType.typeid == value.type);
+	Object value = self.get_at(index);
+	if ($EnumType.typeid != value.type) return CastResult.TYPE_MISMATCH?;
 	return ($EnumType)value.i;
 }

 /**
- * @require o.is_keyable()
+ * @require self.is_keyable()
 **/
-fn bool! Object.get_bool(Object* o, String key)
+fn bool! Object.get_bool(&self, String key)
 {
-	Object* value = o.get(key)?;
-	assert(value.is_bool());
+	Object* value = self.get(key)!;
+	if (!value.is_bool()) return CastResult.TYPE_MISMATCH?;
 	return value.b;
 }


 /**
- * @require o.is_indexable()
+ * @require self.is_indexable()
 **/
-fn bool Object.get_bool_at(Object* o, usz index)
+fn bool! Object.get_bool_at(&self, usz index)
 {
-	Object* value = o.get_at(index);
-	assert(value.is_bool());
+	Object* value = self.get_at(index);
+	if (!value.is_bool()) return CastResult.TYPE_MISMATCH?;
 	return value.b;
 }

 /**
- * @require o.is_keyable()
+ * @require self.is_keyable()
 **/
-fn double! Object.get_float(Object* o, String key)
+fn double! Object.get_float(&self, String key)
 {
-	Object* value = o.get(key)?;
+	Object* value = self.get(key)!;
 	switch (value.type.kindof)
 	{
 		case SIGNED_INT:
@@ -441,16 +445,16 @@ fn double! Object.get_float(Object* o, String key)
 		case FLOAT:
 			return value.f;
 		default:
-			unreachable();
+			return CastResult.TYPE_MISMATCH?;
 	}
 }

 /**
- * @require o.is_indexable()
+ * @require self.is_indexable()
 **/
-fn double Object.get_float_at(Object* o, usz index)
+fn double! Object.get_float_at(&self, usz index)
 {
-	Object* value = o.get_at(index);
+	Object* value = self.get_at(index);
 	switch (value.type.kindof)
 	{
 		case SIGNED_INT:
@@ -460,19 +464,19 @@ fn double Object.get_float_at(Object* o, usz index)
 		case FLOAT:
 			return value.f;
 		default:
-			unreachable();
+			return CastResult.TYPE_MISMATCH?;
 	}
 }

-fn Object* Object.get_or_create_obj(Object* o, String key)
+fn Object* Object.get_or_create_obj(&self, String key)
 {
-	if (try obj = o.get(key) && !obj.is_null()) return obj;
-	Object* container = new_obj();
-	o.set(key, container);
+	if (try obj = self.get(key) && !obj.is_null()) return obj;
+	Object* container = new_obj(self.allocator);
+	self.set(key, container);
 	return container;
 }

-typedef ObjectInternalMap @private = HashMap<String, Object*>;
-typedef ObjectInternalList @private = List<Object*>;
-typedef ObjectInternalMapEntry @private = Entry<String, Object*>;
+def ObjectInternalMap = HashMap(<String, Object*>) @private;
+def ObjectInternalList = List(<Object*>) @private;
+def ObjectInternalMapEntry = Entry(<String, Object*>) @private;

--- a/lib/std/collections/priorityqueue.c3
+++ b/lib/std/collections/priorityqueue.c3
@@ -20,94 +20,126 @@
 //  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 //  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 //  SOFTWARE.
-module std::collections::priorityqueue<Type>;
+module std::collections::priorityqueue(<Type>);
+import std::collections::priorityqueue::private;
+
+distinct PriorityQueue = inline PrivatePriorityQueue(<Type, false>);
+distinct PriorityQueueMax = inline PrivatePriorityQueue(<Type, true>);
+
+module std::collections::priorityqueue::private(<Type, MAX>);
 import std::collections::list;

-typedef Heap = List<Type>;
+def Heap = List(<Type>);

-struct PriorityQueue
+struct PrivatePriorityQueue (Printable)
 {
 	Heap heap;
-	bool max;  // true if max-heap, false if min-heap
 }

-fn void PriorityQueue.push(PriorityQueue* pq, Type element)
+fn void PrivatePriorityQueue.init_new(&self, usz initial_capacity = 16, Allocator* allocator = mem::heap()) @inline
 {
-	pq.heap.push(element);
-	usz i = pq.heap.len() - 1;
+	self.heap.init_new(initial_capacity, allocator);
+}
+
+fn void PrivatePriorityQueue.init_temp(&self, usz initial_capacity = 16) @inline
+{
+	self.heap.init_new(initial_capacity, mem::temp()) @inline;
+}
+
+fn void PrivatePriorityQueue.push(&self, Type element)
+{
+	self.heap.push(element);
+	usz i = self.heap.len() - 1;
 	while (i > 0)
 	{
 		usz parent = (i - 1) / 2;
-		if ((pq.max && greater(pq.heap.get(i), pq.heap.get(parent))) || (!pq.max && less(pq.heap.get(i), pq.heap.get(parent))))
-		{
-			pq.heap.swap(i, parent);
-			i = parent;
-			continue;
-		}
-		break;
+		Type item = self.heap[i];
+		Type parent_item = self.heap[parent];
+		$if MAX:
+			bool ok = greater(item, parent_item);
+		$else
+			bool ok = less(item, parent_item);
+		$endif
+		if (!ok) break;
+		self.heap.swap(i, parent);
+		i = parent;
 	}
 }

 /**
-* @require pq != null
+* @require self != null
 */
-fn Type! PriorityQueue.pop(PriorityQueue* pq)
+fn Type! PrivatePriorityQueue.pop(&self)
 {
 	usz i = 0;
-	usz len = pq.heap.len() @inline;
-	if (!len) return IteratorResult.NO_MORE_ELEMENT!;
+	usz len = self.heap.len();
+	if (!len) return IteratorResult.NO_MORE_ELEMENT?;
 	usz newCount = len - 1;
-	pq.heap.swap(0, newCount);
+	self.heap.swap(0, newCount);
 	while ((2 * i + 1) < newCount)
 	{
 		usz j = 2 * i + 1;
-		if (((j + 1) < newCount) &&
-			((pq.max && greater(pq.heap.get(j + 1), pq.heap[j]))
-				|| (!pq.max && less(pq.heap.get(j + 1), pq.heap.get(j)))))
+		Type itemj = self.heap[j];
+		if ((j + 1) < newCount)
 		{
-			j++;
+			Type nextj = self.heap[j + 1];
+			$if MAX:
+				bool ok = greater(nextj, itemj);
+			$else
+				bool ok = less(nextj, itemj);
+			$endif
+			if (ok) j++;
 		}
-		if ((pq.max && less(pq.heap.get(i), pq.heap.get(j))) || (!pq.max && greater(pq.heap.get(i), pq.heap.get(j))))
-		{
-			pq.heap.swap(i, j);
-			i = j;
-			continue;
-		}
-		break;
+		Type item = self.heap[i];
+		$if MAX:
+			bool ok = less(item, itemj);
+		$else
+			bool ok = greater(item, itemj);
+		$endif
+		if (!ok) break;
+		self.heap.swap(i, j);
+		i = j;
 	}

-	return pq.heap.pop();
+	return self.heap.pop();
+}
+
+fn Type! PrivatePriorityQueue.peek(&self)
+{
+	if (!self.len()) return IteratorResult.NO_MORE_ELEMENT?;
+	return self.heap.get(0);
+}
+
+fn void PrivatePriorityQueue.free(&self)
+{
+	self.heap.free();
+}
+
+fn usz PrivatePriorityQueue.len(&self) @operator(len)
+{
+	return self.heap.len();
+}
+
+fn bool PrivatePriorityQueue.is_empty(&self)
+{
+	return self.heap.is_empty();
 }

 /**
- * @require pq != null
+ * @require index < self.len()
 */
-fn Type! PriorityQueue.peek(PriorityQueue* pq)
+fn Type PrivatePriorityQueue.peek_at(&self, usz index) @operator([])
 {
-	if (!pq.len()) return IteratorResult.NO_MORE_ELEMENT!;
-	return pq.heap.get(0);
+	return self.heap[index];
 }

-/**
- * @require pq != null
- */
-fn void PriorityQueue.free(PriorityQueue* pq)
+fn usz! PrivatePriorityQueue.to_format(&self, Formatter* formatter) @dynamic
 {
-	pq.heap.free();
+	return self.heap.to_format(formatter);
 }

-/**
- * @require pq != null
- */
-fn usz PriorityQueue.len(PriorityQueue* pq) @operator(len)
+fn String PrivatePriorityQueue.to_new_string(&self, Allocator* allocator = mem::heap()) @dynamic
 {
-	return pq.heap.len();
+	return self.heap.to_new_string(allocator);
 }

-/**
- * @require pq != null, index < pq.len()
- */
-fn Type PriorityQueue.peek_at(PriorityQueue* pq, usz index) @operator([])
-{
-	return pq.heap[index];
-}
--- a/lib/std/collections/range.c3
+++ b/lib/std/collections/range.c3
@@ -0,0 +1,84 @@
+/**
+ * @require Type.is_ordered : "The type must be ordered"
+ **/
+module std::collections::range(<Type>);
+
+struct Range (Printable)
+{
+	Type start;
+	Type end;
+}
+
+fn usz Range.len(&self) @operator(len)
+{
+	if (self.end < self.start) return 0;
+	return (usz)(self.end - self.start) + 1;
+}
+
+fn bool Range.contains(&self, Type value) @inline
+{
+	return value >= self.start && value <= self.end;
+}
+
+/**
+ * @require index < self.len() : "Can't index into an empty range"
+ **/
+fn Type Range.get(&self, usz index) @operator([])
+{
+	return (Type)(self.start + (usz)index);
+}
+
+fn String Range.to_new_string(&self, Allocator* allocator = mem::heap()) @dynamic
+{
+	return string::new_format("[%s..%s]", self.start, self.end, .allocator = allocator);
+}
+
+fn String Range.to_tstring(&self)
+{
+	return self.to_new_string(mem::temp());
+}
+
+fn usz! Range.to_format(&self, Formatter* formatter) @dynamic
+{
+	return formatter.printf("[%s..%s]", self.start, self.end)!;
+}
+
+struct ExclusiveRange (Printable)
+{
+	Type start;
+	Type end;
+}
+
+fn usz ExclusiveRange.len(&self) @operator(len)
+{
+	if (self.end < self.start) return 0;
+	return (usz)(self.end - self.start);
+}
+
+fn bool ExclusiveRange.contains(&self, Type value) @inline
+{
+	return value >= self.start && value < self.end;
+}
+
+fn usz! ExclusiveRange.to_format(&self, Formatter* formatter) @dynamic
+{
+	return formatter.printf("[%s..<%s]", self.start, self.end)!;
+}
+
+fn String ExclusiveRange.to_new_string(&self, Allocator* allocator = mem::heap()) @dynamic
+{
+	return string::new_format("[%s..<%s]", self.start, self.end, .allocator = allocator);
+}
+
+fn String ExclusiveRange.to_tstring(&self)
+{
+	return self.to_new_string(mem::temp());
+}
+
+/**
+ * @require index < self.len() : "Can't index into an empty range"
+ **/
+fn Type ExclusiveRange.get(&self, usz index) @operator([])
+{
+	return (Type)(self.start + index);
+}
--- a/lib/std/collections/ringbuffer.c3
+++ b/lib/std/collections/ringbuffer.c3
@@ -0,0 +1,103 @@
+module std::collections::ringbuffer(<Type, SIZE>);
+
+struct RingBuffer
+{
+	Type[SIZE] buf;
+	usz written;
+	usz head;
+}
+
+fn void RingBuffer.init(&self) @inline
+{
+	*self = {};
+}
+
+fn void RingBuffer.putc(&self, Type c)
+{
+	if (self.written < SIZE)
+	{
+		self.buf[self.written] = c;
+		self.written++;
+	}
+	else
+	{
+		self.buf[self.head] = c;
+		self.head = (self.head + 1) % SIZE;
+	}
+}
+
+fn Type RingBuffer.getc(&self, usz index)
+{
+	index %= SIZE;
+	usz avail = SIZE - self.head;
+	if (index < avail)
+	{
+		return self.buf[self.head + index];
+	}
+	return self.buf[index - avail];
+}
+
+fn Type! RingBuffer.popc(&self)
+{
+	switch
+	{
+		case self.written == 0:
+			return SearchResult.MISSING?;
+		case self.written < SIZE:
+			self.written--;
+			return self.buf[self.written];
+		default:
+			self.head = (self.head - 1) % SIZE;
+			return self.buf[self.head];
+	}
+}
+
+fn usz RingBuffer.get(&self, usz index, Type[] buffer)
+{
+	index %= SIZE;
+	if (self.written < SIZE)
+	{
+		if (index >= self.written) return 0;
+		usz end = self.written - index;
+		usz n = min(end, buffer.len);
+		buffer[:n] = self.buf[index:n];
+		return n;
+	}
+	usz end = SIZE - self.head;
+	if (index >= end)
+	{
+		index -= end;
+		if (index >= self.head) return 0;
+		usz n = min(self.head - index, buffer.len);
+		buffer[:n] = self.buf[index:n];
+		return n;
+	}
+	if (buffer.len <= SIZE - index)
+	{
+		usz n = buffer.len;
+		buffer[:n] = self.buf[self.head + index:n];
+		return n;
+	}
+	usz n1 = SIZE - index;
+	buffer[:n1] = self.buf[self.head + index:n1];
+	buffer = buffer[n1..];
+	index -= n1;
+	usz n2 = min(self.head - index, buffer.len);
+	buffer[:n2] = self.buf[index:n2];
+	return n1 + n2;
+}
+
+fn void RingBuffer.push(&self, Type[] buffer)
+{
+	usz i;
+	while (self.written < SIZE && i < buffer.len)
+	{
+		self.buf[self.written] = buffer[i++];
+		self.written++;
+	}
+	foreach (c : buffer[i..])
+	{
+		self.buf[self.head] = c;
+		self.head = (self.head + 1) % SIZE;
+	}
+}
--- a/lib/std/collections/tuple.c3
+++ b/lib/std/collections/tuple.c3
@@ -0,0 +1,16 @@
+module std::collections::tuple(<Type1, Type2>);
+
+struct Tuple
+{
+	Type1 first;
+	Type2 second;
+}
+
+module std::collections::triple(<Type1, Type2, Type3>);
+
+struct Triple
+{
+	Type1 first;
+	Type2 second;
+	Type3 third;
+}
--- a/lib/std/core/allocators/arena_allocator.c3
+++ b/lib/std/core/allocators/arena_allocator.c3
@@ -3,147 +3,114 @@
 // a copy of which can be found in the LICENSE_STDLIB file.
 module std::core::mem::allocator;

-struct ArenaAllocator
+struct ArenaAllocator (Allocator)
 {
-	inline Allocator allocator;
 	char[] data;
 	usz used;
 }

 /**
 * Initialize a memory arena for use using the provided bytes.
- *
- * @require this != null
 **/
-fn void ArenaAllocator.init(ArenaAllocator* this, char[] data)
+fn void ArenaAllocator.init(&self, char[] data)
 {
-	this.function = &arena_allocator_function;
-	this.data = data;
-	this.used = 0;
+	self.data = data;
+	self.used = 0;
 }

-/**
- * @require this != null
- **/
-fn void ArenaAllocator.reset(ArenaAllocator* this)
+fn void ArenaAllocator.clear(&self)
 {
-	this.used = 0;
+	self.used = 0;
 }

-struct ArenaAllocatorHeader
+struct ArenaAllocatorHeader @local
 {
 	usz size;
 	char[*] data;
 }
-/**
- * @require !alignment || math::is_power_of_2(alignment)
- * @require data `unexpectedly missing the allocator`
- */
-fn void*! arena_allocator_function(Allocator* data, usz size, usz alignment, usz offset, void* old_pointer, AllocationKind kind) @private
+
+fn void ArenaAllocator.release(&self, void* ptr, bool) @dynamic
 {
-	ArenaAllocator* arena = (ArenaAllocator*)data;
-	bool clear = false;
-	switch (kind)
+	if (!ptr) return;
+	assert((uptr)ptr >= (uptr)self.data.ptr, "Pointer originates from a different allocator.");
+	ArenaAllocatorHeader* header = ptr - ArenaAllocatorHeader.sizeof;
+	// Reclaim memory if it's the last element.
+	if (ptr + header.size == &self.data[self.used])
 	{
-		case CALLOC:
-		case ALIGNED_CALLOC:
-			clear = true;
-			nextcase;
-		case ALLOC:
-		case ALIGNED_ALLOC:
-			assert(!old_pointer, "Unexpected old pointer for alloc.");
-			if (!size) return null;
-			alignment = alignment_for_allocation(alignment);
-			void* mem = arena._alloc(size, alignment, offset)?;
-			if (clear) mem::clear(mem, size, mem::DEFAULT_MEM_ALIGNMENT);
-        	return mem;
-		case ALIGNED_REALLOC:
-		case REALLOC:
-			if (!size) nextcase FREE;
-			if (!old_pointer) nextcase ALLOC;
-			alignment = alignment_for_allocation(alignment);
-			return arena._realloc(old_pointer, size, alignment, offset)?;
-		case ALIGNED_FREE:
-		case FREE:
-			if (!old_pointer) return null;
-			assert((uptr)old_pointer >= (uptr)arena.data.ptr, "Pointer originates from a different allocator.");
-			ArenaAllocatorHeader* header = old_pointer - ArenaAllocatorHeader.sizeof;
-			// Reclaim memory if it's the last element.
-			if (old_pointer + header.size == &arena.data[arena.used])
-        	{
-        		arena.used -= header.size + ArenaAllocatorHeader.sizeof;
-        	}
-        	return null;
-        case MARK:
-            return (void*)(uptr)arena.used;
-		case RESET:
-			arena.used = size;
-			return null;
+		self.used -= header.size + ArenaAllocatorHeader.sizeof;
 	}
-	unreachable();
 }
+fn usz ArenaAllocator.mark(&self) @dynamic => self.used;
+fn void ArenaAllocator.reset(&self, usz mark) @dynamic => self.used = mark;

 /**
- * @require alignment > 0 `alignment must be non zero`
- * @require math::is_power_of_2(alignment)
- * @require size > 0
+ * @require !alignment || math::is_power_of_2(alignment)
 * @require alignment <= mem::MAX_MEMORY_ALIGNMENT `alignment too big`
 * @require offset <= mem::MAX_MEMORY_ALIGNMENT `offset too big`
 * @require offset <= size && offset >= 0
 * @require mem::aligned_offset(offset, ArenaAllocatorHeader.alignof) == offset
- * @require this != null
 **/
-fn void*! ArenaAllocator._alloc(ArenaAllocator* this, usz size, usz alignment, usz offset) @private
+fn void*! ArenaAllocator.acquire(&self, usz size, bool clear, usz alignment, usz offset) @dynamic
 {
-	usz total_len = this.data.len;
-	if (size > total_len) return AllocationFailure.CHUNK_TOO_LARGE!;
-    void* start_mem = this.data.ptr;
-	void* unaligned_pointer_to_offset = start_mem + this.used + ArenaAllocatorHeader.sizeof + offset;
+	if (!size) return null;
+	alignment = alignment_for_allocation(alignment);
+	usz total_len = self.data.len;
+	if (size > total_len) return AllocationFailure.CHUNK_TOO_LARGE?;
+	void* start_mem = self.data.ptr;
+	void* unaligned_pointer_to_offset = start_mem + self.used + ArenaAllocatorHeader.sizeof + offset;
 	void* aligned_pointer_to_offset = mem::aligned_pointer(unaligned_pointer_to_offset, alignment);
-	usz end = (usz)(aligned_pointer_to_offset - this.data.ptr) + size - offset;
-	if (end > total_len) return AllocationFailure.OUT_OF_MEMORY!;
-	this.used = end;
-	void *mem = aligned_pointer_to_offset - offset;
+	usz end = (usz)(aligned_pointer_to_offset - self.data.ptr) + size - offset;
+	if (end > total_len) return AllocationFailure.OUT_OF_MEMORY?;
+	self.used = end;
+	void* mem = aligned_pointer_to_offset - offset;
 	ArenaAllocatorHeader* header = mem - ArenaAllocatorHeader.sizeof;
 	header.size = size;
+	if (clear) mem::clear(mem, size, mem::DEFAULT_MEM_ALIGNMENT);
 	return mem;
 }

 /**
- * @require alignment > 0 `alignment must be non zero`
- * @require math::is_power_of_2(alignment)
- * @require size > 0
+ * @require !alignment || math::is_power_of_2(alignment)
 * @require alignment <= mem::MAX_MEMORY_ALIGNMENT `alignment too big`
 * @require offset <= mem::MAX_MEMORY_ALIGNMENT `offset too big`
 * @require offset <= size && offset >= 0
 * @require mem::aligned_offset(offset, ArenaAllocatorHeader.alignof) == offset
- * @require this != null
 **/
-fn void*! ArenaAllocator._realloc(ArenaAllocator* this, void *old_pointer, usz size, usz alignment, usz offset) @private
+fn void*! ArenaAllocator.resize(&self, void *old_pointer, usz size, usz alignment, usz offset) @dynamic
 {
-	assert(old_pointer >= this.data.ptr, "Pointer originates from a different allocator.");
-	usz total_len = this.data.len;
-	if (size > total_len) return AllocationFailure.CHUNK_TOO_LARGE!;
+	if (!size)
+	{
+		self.release(old_pointer, alignment > 0);
+		return null;
+	}
+	if (!old_pointer)
+	{
+		return self.acquire(size, true, alignment, offset);
+	}
+	alignment = alignment_for_allocation(alignment);
+	assert(old_pointer >= self.data.ptr, "Pointer originates from a different allocator.");
+	usz total_len = self.data.len;
+	if (size > total_len) return AllocationFailure.CHUNK_TOO_LARGE?;
 	ArenaAllocatorHeader* header = old_pointer - ArenaAllocatorHeader.sizeof;
 	usz old_size = header.size;
 	// Do last allocation and alignment match?
-	if (&this.data[this.used] == old_pointer + old_size && mem::ptr_is_aligned(old_pointer + offset, alignment))
+	if (&self.data[self.used] == old_pointer + old_size && mem::ptr_is_aligned(old_pointer + offset, alignment))
 	{
 		if (old_size >= size)
-        {
-        	this.used -= old_size - size;
-        }
-        else
-        {
-	        usz new_used = this.used + size - old_size;
-            if (new_used > total_len) return AllocationFailure.OUT_OF_MEMORY!;
-            this.used = new_used;
-        }
-        header.size = size;
-        return old_pointer;
+		{
+			self.used -= old_size - size;
+		}
+		else
+		{
+			usz new_used = self.used + size - old_size;
+			if (new_used > total_len) return AllocationFailure.OUT_OF_MEMORY?;
+			self.used = new_used;
+		}
+		header.size = size;
+		return old_pointer;
 	}
 	// Otherwise just allocate new memory.
-	void* mem = this._alloc(size, alignment, offset)?;
+	void* mem = self.acquire(size, false, alignment, offset)!;
 	mem::copy(mem, old_pointer, old_size, mem::DEFAULT_MEM_ALIGNMENT, mem::DEFAULT_MEM_ALIGNMENT);
 	return mem;
 }
--- a/lib/std/core/allocators/dynamic_arena.c3
+++ b/lib/std/core/allocators/dynamic_arena.c3
@@ -1,12 +1,10 @@
 // Copyright (c) 2021 Christoffer Lerno. All rights reserved.
 // Use of this source code is governed by the MIT license
 // a copy of which can be found in the LICENSE_STDLIB file.
-
 module std::core::mem::allocator;

-struct DynamicArenaAllocator
+struct DynamicArenaAllocator (Allocator)
 {
-	inline Allocator allocator;
 	Allocator* backing_allocator;
 	DynamicArenaPage* page;
 	DynamicArenaPage* unused_page;
@@ -14,48 +12,44 @@ struct DynamicArenaAllocator
 }

 /**
+ * @param [&inout] allocator
 * @require page_size >= 128
- * @require this != null
 **/
-fn void DynamicArenaAllocator.init(DynamicArenaAllocator* this, usz page_size, Allocator* backing_allocator = mem::heap())
+fn void DynamicArenaAllocator.init(&self, usz page_size, Allocator* allocator)
 {
-	this.function = &dynamic_arena_allocator_function;
-	this.page = null;
-	this.unused_page = null;
-	this.page_size = page_size;
-	this.backing_allocator = backing_allocator;
+	self.page = null;
+	self.unused_page = null;
+	self.page_size = page_size;
+	self.backing_allocator = allocator;
 }

-/**
- * @require this != null
- **/
-fn void DynamicArenaAllocator.destroy(DynamicArenaAllocator* this)
+fn void DynamicArenaAllocator.free(&self)
 {
-	DynamicArenaPage* page = this.page;
+	DynamicArenaPage* page = self.page;
 	while (page)
 	{
 		DynamicArenaPage* next_page = page.prev_arena;
-		free(page, .using = this.backing_allocator);
+		self.backing_allocator.free(page);
 		page = next_page;
 	}
-	page = this.unused_page;
+	page = self.unused_page;
 	while (page)
 	{
 		DynamicArenaPage* next_page = page.prev_arena;
-		free(page, .using = this.backing_allocator);
+		self.backing_allocator.free(page);
 		page = next_page;
 	}
-	this.page = null;
-	this.unused_page = null;
+	self.page = null;
+	self.unused_page = null;
 }

-struct DynamicArenaPage
+struct DynamicArenaPage @local
 {
 	void* memory;
 	void* prev_arena;
 	usz total;
 	usz used;
-	void* last_ptr;
+	void* current_stack_ptr;
 }

 struct DynamicArenaChunk @local
@@ -64,26 +58,34 @@ struct DynamicArenaChunk @local
 }

 /**
- * @require ptr && this
- * @require this.page `tried to free pointer on invalid allocator`
+ * @require self.page `tried to free pointer on invalid allocator`
 */
-fn void DynamicArenaAllocator.free(DynamicArenaAllocator* this, void* ptr) @private
+fn void DynamicArenaAllocator.release(&self, void* ptr, bool) @dynamic
 {
-	DynamicArenaPage* current_page = this.page;
-	if (ptr == current_page.last_ptr)
+	if (!ptr) return;
+	DynamicArenaPage* current_page = self.page;
+	if (ptr == current_page.current_stack_ptr)
 	{
 		current_page.used = (usz)((ptr - DEFAULT_SIZE_PREFIX) - current_page.memory);
 	}
-	current_page.last_ptr = null;
+	current_page.current_stack_ptr = null;
 }

 /**
- * @require old_pointer && size > 0
- * @require this.page `tried to realloc pointer on invalid allocator`
+ * @require self.page `tried to realloc pointer on invalid allocator`
 */
-fn void*! DynamicArenaAllocator._realloc(DynamicArenaAllocator* this, void* old_pointer, usz size, usz alignment, usz offset) @local
+fn void*! DynamicArenaAllocator.resize(&self, void* old_pointer, usz size, usz alignment, usz offset) @dynamic
 {
-	DynamicArenaPage* current_page = this.page;
+	if (!size)
+	{
+		self.release(old_pointer, alignment > 0);
+		return null;
+	}
+	if (!old_pointer)
+	{
+		return self.acquire(size, true, alignment, offset);
+	}
+	DynamicArenaPage* current_page = self.page;
 	alignment = alignment_for_allocation(alignment);
 	usz* old_size_ptr = old_pointer - DEFAULT_SIZE_PREFIX;
 	usz old_size = *old_size_ptr;
@@ -91,13 +93,13 @@ fn void*! DynamicArenaAllocator._realloc(DynamicArenaAllocator* this, void* old_
 	if (old_size >= size && mem::ptr_is_aligned(old_pointer, alignment))
 	{
 		*old_size_ptr = size;
-		if (current_page.last_ptr == old_pointer)
+		if (current_page.current_stack_ptr == old_pointer)
 		{
 			current_page.used = (usz)((old_pointer - DEFAULT_SIZE_PREFIX) - current_page.memory);
 		}
 		return old_pointer;
 	}
-	if REUSE: (current_page.last_ptr == old_pointer && mem::ptr_is_aligned(old_pointer, alignment))
+	if REUSE: (current_page.current_stack_ptr == old_pointer && mem::ptr_is_aligned(old_pointer, alignment))
 	{
 		assert(size > old_size);
 		usz add_size = size - old_size;
@@ -106,142 +108,99 @@ fn void*! DynamicArenaAllocator._realloc(DynamicArenaAllocator* this, void* old_
 		current_page.used += add_size;
 		return old_pointer;
 	}
-	void* new_mem = this._alloc(size, alignment, offset)?;
+	void* new_mem = self.acquire(size, false, alignment, offset)!;
 	mem::copy(new_mem, old_pointer, old_size, mem::DEFAULT_MEM_ALIGNMENT);
 	return new_mem;
 }

-fn void DynamicArenaAllocator.reset(DynamicArenaAllocator* this) @private
+fn void DynamicArenaAllocator.reset(&self, usz mark = 0) @dynamic
 {
-	DynamicArenaPage* page = this.page;
-	DynamicArenaPage** unused_page_ptr = &this.unused_page;
-    while (page)
-    {
-        DynamicArenaPage* next_page = page.prev_arena;
-        page.used = 0;
-        DynamicArenaPage* prev_unused = *unused_page_ptr;
-        *unused_page_ptr = page;
-        page.prev_arena = prev_unused;
-        page = next_page;
-    }
-    this.page = page;
+	assert(mark == 0, "Unexpectedly reset dynamic arena allocator with mark %d", mark);
+	DynamicArenaPage* page = self.page;
+	DynamicArenaPage** unused_page_ptr = &self.unused_page;
+	while (page)
+	{
+		DynamicArenaPage* next_page = page.prev_arena;
+		page.used = 0;
+		DynamicArenaPage* prev_unused = *unused_page_ptr;
+		*unused_page_ptr = page;
+		page.prev_arena = prev_unused;
+		page = next_page;
+	}
+	self.page = page;
 }

 /**
 * @require math::is_power_of_2(alignment)
 * @require size > 0
 */
-fn void*! DynamicArenaAllocator._alloc_new(DynamicArenaAllocator* this, usz size, usz alignment, usz offset) @local
+fn void*! DynamicArenaAllocator._alloc_new(&self, usz size, usz alignment, usz offset) @local
 {
 	// First, make sure that we can align it, extending the page size if needed.
-	usz page_size = max(this.page_size, mem::aligned_offset(size + DynamicArenaChunk.sizeof + offset, alignment) - offset);
+	usz page_size = max(self.page_size, mem::aligned_offset(size + DynamicArenaChunk.sizeof + offset, alignment) - offset);

 	// Grab the page without alignment (we do it ourselves)
-	void* mem = this.backing_allocator.alloc(page_size)?;
-	DynamicArenaPage*! page = malloc(DynamicArenaPage, .using = this.backing_allocator);
+	void* mem = self.backing_allocator.alloc_checked(page_size)!;
+	DynamicArenaPage*! page = self.backing_allocator.new(DynamicArenaPage);
 	if (catch err = page)
 	{
-		free(mem, .using = this.backing_allocator);
-		return err!;
+		self.backing_allocator.free(mem);
+		return err?;
 	}
-    page.memory = mem;
-    void* mem_start = mem::aligned_pointer(mem + offset + DynamicArenaChunk.sizeof, alignment) - offset;
-    assert(mem_start + size < mem + page_size);
-    DynamicArenaChunk* chunk = (DynamicArenaChunk*)mem_start - 1;
-    chunk.size = size;
-	page.prev_arena = this.page;
+	page.memory = mem;
+	void* mem_start = mem::aligned_pointer(mem + offset + DynamicArenaChunk.sizeof, alignment) - offset;
+	assert(mem_start + size < mem + page_size);
+	DynamicArenaChunk* chunk = (DynamicArenaChunk*)mem_start - 1;
+	chunk.size = size;
+	page.prev_arena = self.page;
 	page.total = page_size;
 	page.used = mem_start + size - page.memory;
-	this.page = page;
-	page.last_ptr = mem_start;
+	self.page = page;
+	page.current_stack_ptr = mem_start;
 	return mem_start;
 }

 /**
 * @require !alignment || math::is_power_of_2(alignment)
- * @require size > 0
- * @require this
 */
-fn void*! DynamicArenaAllocator._alloc(DynamicArenaAllocator* this, usz size, usz alignment, usz offset) @local
+fn void*! DynamicArenaAllocator.acquire(&self, usz size, bool clear, usz alignment, usz offset) @dynamic
 {
+	if (!size) return null;
 	alignment = alignment_for_allocation(alignment);
-	DynamicArenaPage* page = this.page;
-	if (!page && this.unused_page)
-	{
-		this.page = page = this.unused_page;
-		this.unused_page = page.prev_arena;
-		page.prev_arena = null;
-	}
-    if (!page) return this._alloc_new(size, alignment, offset);
-    void* start = mem::aligned_pointer(page.memory + page.used + DynamicArenaChunk.sizeof + offset, alignment) - offset;
-    usz new_used = start - page.memory + size;
-    if ALLOCATE_NEW: (new_used > page.total)
-    {
-        if ((page = this.unused_page))
-        {
-            start = mem::aligned_pointer(page.memory + page.used + DynamicArenaChunk.sizeof + offset, alignment) - offset;
-            new_used = start + size - page.memory;
-            if (page.total >= new_used)
-            {
-	    		this.unused_page = page.prev_arena;
-    	    	page.prev_arena = this.page;
-    		    this.page = page;
-    		    break ALLOCATE_NEW;
-            }
-        }
- 	    return this._alloc_new(size, alignment, offset);
-    }
-
-    page.used = new_used;
-	assert(start + size == page.memory + page.used);
-    void* mem = start;
-    DynamicArenaChunk* chunk = (DynamicArenaChunk*)mem - 1;
-    chunk.size = size;
-    return mem;
-}
-
-/**
- * @require !alignment || math::is_power_of_2(alignment)
- * @require data `unexpectedly missing the allocator`
- */
-fn void*! dynamic_arena_allocator_function(Allocator* data, usz size, usz alignment, usz offset, void* old_pointer, AllocationKind kind) @private
-{
-	DynamicArenaAllocator* allocator = (DynamicArenaAllocator*)data;
-	switch (kind)
-	{
-		case CALLOC:
-		case ALIGNED_CALLOC:
-			assert(!old_pointer, "Unexpected no old pointer for calloc.");
-			if (!size) return null;
-			void* mem = allocator._alloc(size, alignment, offset)?;
-			mem::clear(mem, size, mem::DEFAULT_MEM_ALIGNMENT);
-			return mem;
-		case ALLOC:
-		case ALIGNED_ALLOC:
-			assert(!old_pointer, "Unexpected no old pointer for alloc.");
-			if (!size) return null;
-			return allocator._alloc(size, alignment, offset);
-		case REALLOC:
-		case ALIGNED_REALLOC:
-			if (!size)
+	DynamicArenaPage* page = self.page;
+	void* ptr = {|
+		if (!page && self.unused_page)
+		{
+			self.page = page = self.unused_page;
+			self.unused_page = page.prev_arena;
+			page.prev_arena = null;
+		}
+		if (!page) return self._alloc_new(size, alignment, offset);
+		void* start = mem::aligned_pointer(page.memory + page.used + DynamicArenaChunk.sizeof + offset, alignment) - offset;
+		usz new_used = start - page.memory + size;
+		if ALLOCATE_NEW: (new_used > page.total)
+		{
+			if ((page = self.unused_page))
 			{
-				if (!old_pointer) return null;
-				allocator.free(old_pointer);
-				return null;
+				start = mem::aligned_pointer(page.memory + page.used + DynamicArenaChunk.sizeof + offset, alignment) - offset;
+				new_used = start + size - page.memory;
+				if (page.total >= new_used)
+				{
+					self.unused_page = page.prev_arena;
+					page.prev_arena = self.page;
+					self.page = page;
+					break ALLOCATE_NEW;
+				}
 			}
-			if (!old_pointer) return allocator._alloc(size, alignment, offset);
-			void* mem = allocator._realloc(old_pointer, size, alignment, offset)?;
-			return mem;
-		case ALIGNED_FREE:
-		case FREE:
-			if (!old_pointer) return null;
-			allocator.free(old_pointer);
-			return null;
-		case MARK:
-			unreachable("Tried to mark a dynamic arena");
-		case RESET:
-			allocator.reset();
-			return null;
-	}
-	unreachable();
+			return self._alloc_new(size, alignment, offset);
+		}
+		page.used = new_used;
+		assert(start + size == page.memory + page.used);
+		void* mem = start;
+		DynamicArenaChunk* chunk = (DynamicArenaChunk*)mem - 1;
+		chunk.size = size;
+		return mem;
+	|}!;
+	if (clear) mem::clear(ptr, size, mem::DEFAULT_MEM_ALIGNMENT);
+	return ptr;
 }
--- a/lib/std/core/allocators/heap_allocator.c3
+++ b/lib/std/core/allocators/heap_allocator.c3
@@ -1,99 +1,95 @@
-// Copyright (c) 2021 Christoffer Lerno. All rights reserved.
+// Copyright (c) 2021-2023 Christoffer Lerno. All rights reserved.
 // Use of this source code is governed by the MIT license
 // a copy of which can be found in the LICENSE_STDLIB file.

 module std::core::mem::allocator;

-typedef MemoryAllocFn = fn char[]!(usz);

-struct SimpleHeapAllocator
+struct SimpleHeapAllocator (Allocator)
 {
-	inline Allocator allocator;
 	MemoryAllocFn alloc_fn;
 	Header* free_list;
 }

 /**
- * @require this "Unexpectedly missing the allocator"
 * @require allocator "An underlying memory provider must be given"
- * @require !this.free_list "The allocator may not be already initialized"
+ * @require !self.free_list "The allocator may not be already initialized"
 **/
-fn void SimpleHeapAllocator.init(SimpleHeapAllocator* this, MemoryAllocFn allocator)
+fn void SimpleHeapAllocator.init(&self, MemoryAllocFn allocator)
 {
-	this.alloc_fn = allocator;
-	this.allocator = { &simple_heap_allocator_function };
-	this.free_list = null;
+	self.alloc_fn = allocator;
+	self.free_list = null;
 }

-/**
- * @require !alignment || math::is_power_of_2(alignment)
- * @require this `unexpectedly missing the allocator`
- */
-fn void*! simple_heap_allocator_function(Allocator* this, usz size, usz alignment, usz offset, void* old_pointer, AllocationKind kind) @private
+fn void*! SimpleHeapAllocator.acquire(&self, usz size, bool clear, usz alignment, usz offset) @dynamic
 {
-	SimpleHeapAllocator* heap = (SimpleHeapAllocator*)this;
-	switch (kind)
-    {
-        case ALIGNED_ALLOC:
-            return @aligned_alloc(heap._alloc, size, alignment, offset);
-		case ALLOC:
-            return heap._alloc(size);
-        case ALIGNED_CALLOC:
-            return @aligned_calloc(heap._calloc, size, alignment, offset);
-    	case CALLOC:
-            return heap._calloc(size);
-        case ALIGNED_REALLOC:
-            if (!size) nextcase ALIGNED_FREE;
-            if (!old_pointer) nextcase ALIGNED_CALLOC;
-            return @aligned_realloc(heap._calloc, heap._free, old_pointer, size, alignment, offset);
-        case REALLOC:
-            if (!size) nextcase FREE;
-            if (!old_pointer) nextcase CALLOC;
-            return heap._realloc(old_pointer, size);
-        case RESET:
-            return AllocationFailure.UNSUPPORTED_OPERATION!;
-        case ALIGNED_FREE:
-            @aligned_free(heap._free, old_pointer)?;
-            return null;
-        case FREE:
-            heap._free(old_pointer);
-            return null;
-        default:
-            unreachable();
+	if (!size) return null;
+	if (clear)
+	{
+		return alignment > 0 ? @aligned_calloc(self._calloc, size, alignment, offset) : self._calloc(size);
+	}
+	return alignment > 0 ? @aligned_alloc(self._alloc, size, alignment, offset) : self._alloc(size);
+}
+
+fn void*! SimpleHeapAllocator.resize(&self, void* old_pointer, usz size, usz alignment, usz offset) @dynamic
+{
+	if (!size)
+	{
+		self.release(old_pointer, alignment > 0);
+		return null;
+	}
+	if (!old_pointer)
+	{
+		return self.acquire(size, true, alignment, offset);
+	}
+	return alignment > 0
+		? @aligned_realloc(self._calloc, self._free, old_pointer, size, alignment, offset)
+		:  self._realloc(old_pointer, size);
+}
+
+fn void SimpleHeapAllocator.release(&self, void* old_pointer, bool aligned) @dynamic
+{
+	if (aligned)
+	{
+		@aligned_free(self._free, old_pointer)!!;
+	}
+	else
+	{
+		self._free(old_pointer);
 	}
 }

 /**
- * @require this && old_pointer && bytes > 0
+ * @require old_pointer && bytes > 0
 **/
-fn void*! SimpleHeapAllocator._realloc(SimpleHeapAllocator* this, void* old_pointer, usz bytes)
+fn void*! SimpleHeapAllocator._realloc(&self, void* old_pointer, usz bytes) @local
 {
 	// Find the block header.
 	Header* block = (Header*)old_pointer - 1;
 	if (block.size >= bytes) return old_pointer;
-	void* new = this._alloc(bytes)?;
+	void* new = self._alloc(bytes)!;
 	usz max_to_copy = math::min(block.size, bytes);
 	mem::copy(new, old_pointer, max_to_copy);
-	this._free(old_pointer);
+	self._free(old_pointer);
 	return new;
 }

-fn void*! SimpleHeapAllocator._calloc(SimpleHeapAllocator* this, usz bytes) @local
+fn void*! SimpleHeapAllocator._calloc(&self, usz bytes) @local
 {
-	void* data = this._alloc(bytes)?;
+	void* data = self._alloc(bytes)!;
 	mem::clear(data, bytes, mem::DEFAULT_MEM_ALIGNMENT);
 	return data;
 }

-fn void*! SimpleHeapAllocator._alloc(SimpleHeapAllocator* this, usz bytes) @local
+fn void*! SimpleHeapAllocator._alloc(&self, usz bytes) @local
 {
 	usz aligned_bytes = mem::aligned_offset(bytes, mem::DEFAULT_MEM_ALIGNMENT);
-    if (!this.free_list)
-    {
-		this.add_block(aligned_bytes)?;
-    }
+	if (!self.free_list)
+	{
+		self.add_block(aligned_bytes)!;
+	}

-	Header* current = this.free_list;
+	Header* current = self.free_list;
 	Header* previous = current;
 	while (current)
 	{
@@ -102,21 +98,21 @@ fn void*! SimpleHeapAllocator._alloc(SimpleHeapAllocator* this, usz bytes) @loca
 			case current.size >= aligned_bytes && current.size <= aligned_bytes + Header.sizeof + 64:
 				if (current == previous)
 				{
-					this.free_list = current.next;
+					self.free_list = current.next;
 				}
 				else
 				{
 					previous.next = current.next;
-                }
-                current.next = null;
-                return current + 1;
-            case current.size > aligned_bytes:
+				}
+				current.next = null;
+				return current + 1;
+			case current.size > aligned_bytes:
 				Header* unallocated = (Header*)((char*)current + aligned_bytes + Header.sizeof);
 				unallocated.size = current.size - aligned_bytes;
 				unallocated.next = current.next;
-				if (current == this.free_list)
+				if (current == self.free_list)
 				{
-					this.free_list = unallocated;
+					self.free_list = unallocated;
 				}
 				else
 				{
@@ -130,22 +126,22 @@ fn void*! SimpleHeapAllocator._alloc(SimpleHeapAllocator* this, usz bytes) @loca
 				current = current.next;
 		}
 	}
-	this.add_block(aligned_bytes)?;
-	return this.alloc(aligned_bytes);
+	self.add_block(aligned_bytes)!;
+	return self._alloc(aligned_bytes);
 }

-fn void! SimpleHeapAllocator.add_block(SimpleHeapAllocator* this, usz aligned_bytes) @local
+fn void! SimpleHeapAllocator.add_block(&self, usz aligned_bytes) @local
 {
 	assert(mem::aligned_offset(aligned_bytes, mem::DEFAULT_MEM_ALIGNMENT) == aligned_bytes);
-	char[] result = this.alloc_fn(aligned_bytes + Header.sizeof)?;
+	char[] result = self.alloc_fn(aligned_bytes + Header.sizeof)!;
 	Header* new_block = (Header*)result.ptr;
 	new_block.size = result.len - Header.sizeof;
 	new_block.next = null;
-	this._free(new_block + 1);
+	self._free(new_block + 1);
 }


-fn void SimpleHeapAllocator._free(SimpleHeapAllocator* this, void* ptr) @local
+fn void SimpleHeapAllocator._free(&self, void* ptr) @local
 {
 	// Empty ptr -> do nothing.
 	if (!ptr) return;
@@ -153,15 +149,15 @@ fn void SimpleHeapAllocator._free(SimpleHeapAllocator* this, void* ptr) @local
 	// Find the block header.
 	Header* block = (Header*)ptr - 1;

-	// No free list? Then just return this.
-	if (!this.free_list)
+	// No free list? Then just return self.
+	if (!self.free_list)
 	{
-		this.free_list = block;
+		self.free_list = block;
 		return;
 	}

 	// Find where in the list it should be inserted.
-	Header* current = this.free_list;
+	Header* current = self.free_list;
 	Header* prev = current;
 	while (current)
 	{
@@ -178,46 +174,46 @@ fn void SimpleHeapAllocator._free(SimpleHeapAllocator* this, void* ptr) @local
 	if (current)
 	{
 		// Insert after the current block.
-        // Are the blocks adjacent?
-        if (current == (Header*)((char*)(block + 1) + block.size))
-        {
-            // Merge
-    		block.size += current.size + Header.sizeof;
-            block.next = current.next;
-        }
-        else
-        {
-            // Chain to current
-            block.next = current;
-        }
+		// Are the blocks adjacent?
+		if (current == (Header*)((char*)(block + 1) + block.size))
+		{
+			// Merge
+			block.size += current.size + Header.sizeof;
+			block.next = current.next;
+		}
+		else
+		{
+			// Chain to current
+			block.next = current;
+		}
 	}
 	if (prev == current)
 	{
 		// Swap new start of free list
-		this.free_list = block;
+		self.free_list = block;
 	}
 	else
 	{
 		// Prev adjacent?
 		if (block == (Header*)((char*)(prev + 1) + prev.size))
 		{
-    		prev.size += block.size + Header.sizeof;
+			prev.size += block.size + Header.sizeof;
 			prev.next = block.next;
 		}
 		else
 		{
-	        // Link prev to block
-	        prev.next = block;
+			// Link prev to block
+			prev.next = block;
 		}
 	}
 }

-union Header @private
+union Header @local
 {
 	struct
 	{
 		Header* next;
-  	    usz size;
-    }
-    usz align;
+		usz size;
+	}
+	usz align;
 }
--- a/lib/std/core/allocators/libc_allocator.c3
+++ b/lib/std/core/allocators/libc_allocator.c3
@@ -0,0 +1,63 @@
+// Copyright (c) 2021 Christoffer Lerno. All rights reserved.
+// Use of this source code is governed by the MIT license
+// a copy of which can be found in the LICENSE_STDLIB file.
+
+module std::core::mem::allocator;
+import libc;
+
+const LibcAllocator LIBC_ALLOCATOR = {};
+
+
+distinct LibcAllocator (Allocator) = uptr;
+
+fn void*! LibcAllocator.acquire(&self, usz bytes, bool clear, usz alignment, usz offset) @dynamic
+{
+	assert(alignment != 0 || offset == 0);
+	if (clear)
+	{
+		void* data = alignment ? @aligned_calloc(fn void*(usz bytes) => libc::calloc(bytes, 1), bytes, alignment, offset)!! : libc::calloc(bytes, 1);
+        return data ?: AllocationFailure.OUT_OF_MEMORY?;
+	}
+	else
+	{
+		void* data = alignment ? @aligned_alloc(libc::malloc, bytes, alignment, offset)!! : libc::malloc(bytes);
+        if (!data) return AllocationFailure.OUT_OF_MEMORY?;
+        $if env::TESTING:
+		    for (usz i = 0; i < bytes; i++) ((char*)data)[i] = 0xAA;
+        $endif
+        return data;
+	}
+}
+
+fn void*! LibcAllocator.resize(&self, void* old_ptr, usz new_bytes, usz alignment, usz offset) @dynamic
+{
+	assert(alignment != 0 || offset == 0);
+	if (!new_bytes)
+	{
+		self.release(old_ptr, alignment > 0);
+		return null;
+	}
+	if (!old_ptr)
+	{
+		return self.acquire(new_bytes, true, alignment, offset);
+	}
+	if (alignment)
+	{
+		void* data = @aligned_realloc(fn void*(usz bytes) => libc::calloc(bytes, 1), libc::free, old_ptr, new_bytes, alignment, offset)!!;
+		return data ?: AllocationFailure.OUT_OF_MEMORY?;
+	}
+	return libc::realloc(old_ptr, new_bytes) ?: AllocationFailure.OUT_OF_MEMORY?;
+}
+
+
+fn void LibcAllocator.release(&self, void* old_ptr, bool aligned) @dynamic
+{
+	if (aligned)
+	{
+		@aligned_free(libc::free, old_ptr)!!;
+	}
+	else
+	{
+		libc::free(old_ptr);
+	}
+}
--- a/lib/std/core/allocators/mem_allocator_fn.c3
+++ b/lib/std/core/allocators/mem_allocator_fn.c3
@@ -1,136 +0,0 @@
-// Copyright (c) 2021 Christoffer Lerno. All rights reserved.
-// Use of this source code is governed by the MIT license
-// a copy of which can be found in the LICENSE_STDLIB file.
-
-module std::core::mem::allocator;
-import libc;
-
-const Allocator _NULL_ALLOCATOR @private = { &null_allocator_fn };
-const Allocator _SYSTEM_ALLOCATOR @private = { &libc_allocator_fn };
-
-fn void*! null_allocator_fn(Allocator* this, usz bytes, usz alignment, usz offset, void* old_pointer, AllocationKind kind) @private
-{
-	switch (kind)
-	{
-		case ALLOC:
-        case CALLOC:
-        case REALLOC:
-        case ALIGNED_ALLOC:
-        case ALIGNED_REALLOC:
-        case ALIGNED_CALLOC:
-			return AllocationFailure.OUT_OF_MEMORY!;
-		default:
-			return null;
-	}
-}
-
-struct AlignedBlock
-{
-	usz len;
-	void* start;
-}
-
-/**
- * @require bytes > 0
- * @require alignment > 0
- **/
-macro void*! @aligned_alloc(#alloc_fn, usz bytes, usz alignment, usz offset)
-{
-	usz header = mem::aligned_offset(AlignedBlock.sizeof + offset, alignment) - offset;
-	$if ($checks(#alloc_fn(bytes)?))
-		void* data = #alloc_fn(header + bytes)?;
-	$else
-		void* data = #alloc_fn(header + bytes);
-	$endif
-    void* mem = mem::aligned_pointer(data + header + offset, alignment) - offset;
-	assert(mem > data);
-	AlignedBlock* desc = (AlignedBlock*)mem - 1;
-	*desc = { bytes, data };
-	return mem;
-}
-
-/**
- * @require bytes > 0
- * @require alignment > 0
- **/
-macro void*! @aligned_calloc(#calloc_fn, usz bytes, usz alignment, usz offset)
-{
-	usz header = mem::aligned_offset(AlignedBlock.sizeof + offset, alignment) - offset;
-	$if ($checks(#calloc_fn(bytes)?))
-		void* data = #calloc_fn(header + bytes)?;
-	$else
-		void* data = #calloc_fn(header + bytes);
-	$endif
-	void* mem = mem::aligned_pointer(data + header + offset, alignment) - offset;
-	AlignedBlock* desc = (AlignedBlock*)mem - 1;
-	assert(mem > data);
-	*desc = { bytes, data };
-	return mem;
-}
-
-/**
- * @require bytes > 0
- * @require alignment > 0
- **/
-macro void*! @aligned_realloc(#calloc_fn, #free_fn, void* old_pointer, usz bytes, usz alignment, usz offset)
-{
-	AlignedBlock* desc = (AlignedBlock*)old_pointer - 1;
-	void* data_start = desc.start;
-    void* new_data = @aligned_calloc(#calloc_fn, bytes, alignment, offset)?;
-	mem::copy(new_data, old_pointer, desc.len > bytes ? desc.len : bytes, mem::DEFAULT_MEM_ALIGNMENT, mem::DEFAULT_MEM_ALIGNMENT);
-	$if ($checks(#free_fn(data_start)?))
-	#free_fn(data_start)?;
-	$else
-	#free_fn(data_start);
-	$endif
-	return new_data;
-}
-
-macro void! @aligned_free(#free_fn, void* old_pointer)
-{
-	AlignedBlock* desc = (AlignedBlock*)old_pointer - 1;
-	$if ($checks(#free_fn(desc.start)?))
-	#free_fn(desc.start)?;
-	$else
-	#free_fn(desc.start);
-	$endif
-}
-
-fn void*! libc_allocator_fn(Allocator* unused, usz bytes, usz alignment, usz offset, void* old_pointer, AllocationKind kind) @inline
-{
-	if (!alignment) alignment = mem::DEFAULT_MEM_ALIGNMENT;
-	assert(math::is_power_of_2(alignment), "Alignment was not a power of 2");
-
-    void* data;
-    switch (kind)
-    {
-        case ALIGNED_ALLOC:
-            data = @aligned_alloc(libc::malloc, bytes, alignment, offset)!!;
-        case ALLOC:
-            data = libc::malloc(bytes);
-        case ALIGNED_CALLOC:
-            data = @aligned_calloc(fn void*(usz bytes) => libc::calloc(bytes, 1), bytes, alignment, offset)!!;
-		case CALLOC:
-            data = libc::calloc(bytes, 1);
-        case ALIGNED_REALLOC:
-            if (!bytes) nextcase ALIGNED_FREE;
-            if (!old_pointer) nextcase ALIGNED_CALLOC;
-            data = @aligned_realloc(fn void*(usz bytes) => libc::calloc(bytes, 1), libc::free, old_pointer, bytes, alignment, offset)!!;
-        case REALLOC:
-            if (!bytes) nextcase FREE;
-            if (!old_pointer) nextcase CALLOC;
-            data = libc::realloc(old_pointer, bytes);
-        case RESET:
-            return AllocationFailure.UNSUPPORTED_OPERATION!;
-        case ALIGNED_FREE:
-            @aligned_free(libc::free, old_pointer)!!;
-            return null;
-        case FREE:
-            libc::free(old_pointer);
-            return null;
-        default:
-            unreachable();
-    }
-    if (!data) return AllocationFailure.OUT_OF_MEMORY!;
-    return data;
-}
--- a/lib/std/core/allocators/on_stack_allocator.c3
+++ b/lib/std/core/allocators/on_stack_allocator.c3
@@ -1,34 +1,13 @@
 module std::core::mem::allocator;

-struct OnStackAllocator
+struct OnStackAllocator (Allocator)
 {
-	inline Allocator allocator;
 	Allocator* backing_allocator;
 	char[] data;
 	usz used;
 	OnStackAllocatorExtraChunk* chunk;
 }

-macro void @stack_mem(usz $size; @body(Allocator* mem)) @builtin
-{
-	char[$size] buffer;
-	OnStackAllocator allocator;
-	allocator.init(&buffer, mem::heap());
-	defer allocator.free();
-	@body(&allocator);
-}
-
-macro void @stack_pool(usz $size; @body) @builtin
-{
-	char[$size] buffer;
-	OnStackAllocator allocator;
-	allocator.init(&buffer, mem::heap());
-	defer allocator.free();
-	mem::@scoped(&allocator)
-	{
-		@body();
-	};
-}

 struct OnStackAllocatorExtraChunk @local
 {
@@ -38,40 +17,35 @@ struct OnStackAllocatorExtraChunk @local
 }

 /**
+ * @param [&inout] allocator
 * Initialize a memory arena for use using the provided bytes.
- *
- * @require this != null
 **/
-fn void OnStackAllocator.init(OnStackAllocator* this, char[] data, Allocator* using = mem::heap())
+fn void OnStackAllocator.init(&self, char[] data, Allocator* allocator)
 {
-	this.function = &on_stack_allocator_function;
-	this.data = data;
-	this.backing_allocator = using;
-	this.used = 0;
+	self.data = data;
+	self.backing_allocator = allocator;
+	self.used = 0;
 }

-/**
- * @require this != null
- **/
-fn void OnStackAllocator.free(OnStackAllocator* this)
+fn void OnStackAllocator.free(&self)
 {
-	OnStackAllocatorExtraChunk* chunk = this.chunk;
+	OnStackAllocatorExtraChunk* chunk = self.chunk;
 	while (chunk)
 	{
 		if (chunk.is_aligned)
 		{
-			this.backing_allocator.free_aligned(chunk.data)!!;
+			self.backing_allocator.free_aligned(chunk.data);
 		}
 		else
 		{
-			this.backing_allocator.free(chunk.data)!!;
+			self.backing_allocator.free(chunk.data);
 		}
 		void* old = chunk;
 		chunk = chunk.prev;
-		this.backing_allocator.free(old)!!;
+		self.backing_allocator.free(old);
 	}
-	this.chunk = null;
-	this.used = 0;
+	self.chunk = null;
+	self.used = 0;
 }

 struct OnStackAllocatorHeader
@@ -80,49 +54,12 @@ struct OnStackAllocatorHeader
 	char[*] data;
 }

-/**
- * @require !alignment || math::is_power_of_2(alignment)
- * @require data `unexpectedly missing the allocator`
- */
-fn void*! on_stack_allocator_function(Allocator* data, usz size, usz alignment, usz offset, void* old_pointer, AllocationKind kind) @private
+fn void OnStackAllocator.release(&self, void* old_pointer, bool aligned) @dynamic
 {
-	OnStackAllocator* allocator = (OnStackAllocator*)data;
-	bool clear = false;
-	switch (kind)
-	{
-		case CALLOC:
-		case ALIGNED_CALLOC:
-			clear = true;
-			nextcase;
-		case ALLOC:
-		case ALIGNED_ALLOC:
-			assert(!old_pointer, "Unexpected old pointer for alloc.");
-			if (!size) return null;
-			return on_stack_allocator_alloc(allocator, size, alignment, offset, clear, kind == AllocationKind.ALIGNED_ALLOC || kind == AllocationKind.ALIGNED_CALLOC);
-		case ALIGNED_REALLOC:
-		case REALLOC:
-			if (!size) nextcase FREE;
-			if (!old_pointer) nextcase ALLOC;
-			return on_stack_allocator_realloc(allocator, old_pointer, size, alignment, offset, kind == AllocationKind.ALIGNED_REALLOC);
-		case ALIGNED_FREE:
-		case FREE:
-			if (!old_pointer) return null;
-			if (allocation_in_stack_mem(allocator, old_pointer)) return null;
-			on_stack_allocator_remove_chunk(allocator, old_pointer);
-			if (kind == AllocationKind.ALIGNED_FREE)
-			{
-				allocator.backing_allocator.free_aligned(old_pointer)?;
-			}
-			else
-			{
-				allocator.backing_allocator.free(old_pointer)?;
-			}
-        	return null;
-        case MARK:
-		case RESET:
-			return AllocationFailure.UNSUPPORTED_OPERATION!;
-	}
-	unreachable();
+	if (!old_pointer) return;
+	if (allocation_in_stack_mem(self, old_pointer)) return;
+	on_stack_allocator_remove_chunk(self, old_pointer);
+	self.release(old_pointer, aligned);
 }

 fn bool allocation_in_stack_mem(OnStackAllocator* a, void* ptr) @local
@@ -139,7 +76,7 @@ fn void on_stack_allocator_remove_chunk(OnStackAllocator* a, void* ptr) @local
 		if (chunk.data == ptr)
 		{
 			*addr = chunk.prev;
-			a.backing_allocator.free(chunk)!!;
+			a.backing_allocator.free(chunk);
 			return;
 		}
 		addr = &chunk.prev;
@@ -164,70 +101,52 @@ fn OnStackAllocatorExtraChunk* on_stack_allocator_find_chunk(OnStackAllocator* a
 * @require alignment <= mem::MAX_MEMORY_ALIGNMENT `alignment too big`
 * @require offset <= mem::MAX_MEMORY_ALIGNMENT `offset too big`
 * @require offset <= size && offset >= 0
- * @require mem::aligned_offset(offset, ArenaAllocatorHeader.alignof) == offset
- * @require a != null
+ * @require mem::aligned_offset(offset, OnStackAllocatorExtraChunk.alignof) == offset
 **/
-fn void*! on_stack_allocator_realloc(OnStackAllocator* a, void* old_pointer, usz size, usz alignment, usz offset, bool aligned) @local @inline
+fn void*! OnStackAllocator.resize(&self, void* old_pointer, usz size, usz alignment, usz offset) @dynamic
 {
-	if (!allocation_in_stack_mem(a, old_pointer))
+	if (!allocation_in_stack_mem(self, old_pointer))
 	{
-		OnStackAllocatorExtraChunk* chunk = on_stack_allocator_find_chunk(a, old_pointer);
+		OnStackAllocatorExtraChunk* chunk = on_stack_allocator_find_chunk(self, old_pointer);
 		assert(chunk, "Tried to realloc pointer not belonging to the allocator");
-		if (aligned)
-		{
-			return chunk.data = a.backing_allocator.realloc_aligned(old_pointer, size, alignment, offset)?;
-		}
-		return chunk.data = a.backing_allocator.realloc(old_pointer, size)?;
+		return chunk.data = self.backing_allocator.resize(old_pointer, size, alignment, offset)!;
 	}

 	OnStackAllocatorHeader* header = old_pointer - OnStackAllocatorHeader.sizeof;
 	usz old_size = header.size;
-	void* mem = on_stack_allocator_alloc(a, size, alignment, offset, true, aligned)?;
+	void* mem = self.acquire(size, true, alignment, offset)!;
 	mem::copy(mem, old_pointer, old_size, mem::DEFAULT_MEM_ALIGNMENT, mem::DEFAULT_MEM_ALIGNMENT);
 	return mem;
 }

-import std::io;
 /**
- * @require size > 0
 * @require alignment <= mem::MAX_MEMORY_ALIGNMENT `alignment too big`
 * @require offset <= mem::MAX_MEMORY_ALIGNMENT `offset too big`
 * @require offset <= size && offset >= 0
- * @require mem::aligned_offset(offset, ArenaAllocatorHeader.alignof) == offset
- * @require a != null
+ * @require offset == 0 || alignment > 0
+ * @require mem::aligned_offset(offset, OnStackAllocatorHeader.alignof) == offset
 **/
-fn void*! on_stack_allocator_alloc(OnStackAllocator* a, usz size, usz alignment, usz offset, bool clear, bool aligned) @local @inline
+fn void*! OnStackAllocator.acquire(&self, usz size, bool clear, usz alignment, usz offset) @dynamic
 {
+	if (size == 0) return null;
+	bool aligned = alignment > 0;
 	alignment = alignment_for_allocation(alignment);
-	usz total_len = a.data.len;
-    void* start_mem = a.data.ptr;
-	void* unaligned_pointer_to_offset = start_mem + a.used + OnStackAllocatorHeader.sizeof + offset;
+	usz total_len = self.data.len;
+	void* start_mem = self.data.ptr;
+	void* unaligned_pointer_to_offset = start_mem + self.used + OnStackAllocatorHeader.sizeof + offset;
 	void* aligned_pointer_to_offset = mem::aligned_pointer(unaligned_pointer_to_offset, alignment);
-	usz end = (usz)(aligned_pointer_to_offset - a.data.ptr) + size - offset;
-
-	Allocator* backing_allocator = a.backing_allocator;
+	usz end = (usz)(aligned_pointer_to_offset - self.data.ptr) + size - offset;
+	Allocator* backing_allocator = self.backing_allocator;

 	if (end > total_len)
 	{
-		OnStackAllocatorExtraChunk* chunk = backing_allocator.alloc(OnStackAllocatorExtraChunk.sizeof)?;
-		defer catch backing_allocator.free(chunk)!!;
-		defer try a.chunk = chunk;
-		*chunk = { .prev = a.chunk, .is_aligned = aligned };
-		void* data @noinit;
-		switch
-		{
-			case !aligned && !clear:
-				data = backing_allocator.alloc(size)?;
-			case aligned && !clear:
-				data = backing_allocator.alloc_aligned(size, alignment, offset)?;
-			case !aligned && clear:
-				data = backing_allocator.calloc(size)?;
-			case aligned && clear:
-				data = backing_allocator.calloc_aligned(size, alignment, offset)?;
-		}
-		return chunk.data = data;
+		OnStackAllocatorExtraChunk* chunk = backing_allocator.alloc_checked(OnStackAllocatorExtraChunk.sizeof)!;
+		defer catch backing_allocator.free(chunk);
+		defer try self.chunk = chunk;
+		*chunk = { .prev = self.chunk, .is_aligned = aligned };
+		return chunk.data = backing_allocator.acquire(size, clear, aligned ? alignment : 0, offset)!;
 	}
-	a.used = end;
+	self.used = end;
 	void *mem = aligned_pointer_to_offset - offset;
 	OnStackAllocatorHeader* header = mem - OnStackAllocatorHeader.sizeof;
 	header.size = size;
--- a/lib/std/core/allocators/temp_allocator.c3
+++ b/lib/std/core/allocators/temp_allocator.c3
@@ -7,9 +7,8 @@ struct TempAllocatorChunk @local
 	char[*] data;
 }

-struct TempAllocator
+struct TempAllocator (Allocator)
 {
-	inline Allocator allocator;
 	Allocator* backing_allocator;
 	TempAllocatorPage* last_page;
 	usz used;
@@ -17,7 +16,6 @@ struct TempAllocator
 	char[*] data;
 }

-
 const usz PAGE_IS_ALIGNED @private = (usz)isz.max + 1u;


@@ -31,98 +29,59 @@ struct TempAllocatorPage
 	char[*] data;
 }

-macro usz TempAllocatorPage.pagesize(TempAllocatorPage* page) => page.size & ~PAGE_IS_ALIGNED;
-macro bool TempAllocatorPage.is_aligned(TempAllocatorPage* page) => page.size & PAGE_IS_ALIGNED == PAGE_IS_ALIGNED;
+macro usz TempAllocatorPage.pagesize(&self) => self.size & ~PAGE_IS_ALIGNED;
+macro bool TempAllocatorPage.is_aligned(&self) => self.size & PAGE_IS_ALIGNED == PAGE_IS_ALIGNED;

 /**
 * @require size >= 16
 **/
-fn TempAllocator*! new_temp(usz size, Allocator* backing_allocator)
+fn TempAllocator*! new_temp(usz size, Allocator* allocator)
 {
-	TempAllocator* allocator = malloc_checked(TempAllocator, .using = backing_allocator, .end_padding = size)?;
-	allocator.last_page = null;
-	allocator.function = &temp_allocator_function;
-	allocator.backing_allocator = backing_allocator;
-	allocator.used = 0;
-	allocator.capacity = size;
-	return allocator;
+	TempAllocator* temp = allocator.alloc_checked(TempAllocator.sizeof + size)!;
+	temp.last_page = null;
+	temp.backing_allocator = allocator;
+	temp.used = 0;
+	temp.capacity = size;
+	return temp;
 }

-/**
- * @require !alignment || math::is_power_of_2(alignment)
- * @require data `unexpectedly missing the allocator`
- */
-fn void*! temp_allocator_function(Allocator* data, usz size, usz alignment, usz offset, void* old_pointer, AllocationKind kind) @private
-{
-	TempAllocator* arena = (TempAllocator*)data;
-	switch (kind)
-	{
-		case CALLOC:
-		case ALIGNED_CALLOC:
-			assert(!old_pointer, "Unexpected old pointer for alloc.");
-			if (!size) return null;
-			return arena._alloc(size, alignment_for_allocation(alignment), offset, true);
-		case ALLOC:
-		case ALIGNED_ALLOC:
-			assert(!old_pointer, "Unexpected old pointer for alloc.");
-			if (!size) return null;
-			return arena._alloc(size, alignment_for_allocation(alignment), offset, false);
-		case ALIGNED_REALLOC:
-		case REALLOC:
-			if (!size) nextcase FREE;
-			if (!old_pointer) nextcase ALLOC;
-			return arena._realloc(old_pointer, size, alignment_for_allocation(alignment), offset);
-		case FREE:
-		case ALIGNED_FREE:
-			if (!old_pointer) return null;
-			arena._free(old_pointer)?;
-        	return null;
-        case MARK:
-            return (void*)(uptr)arena.used;
-		case RESET:
-			arena._reset(size)?;
-			return null;
-	}
-	unreachable();
-}
+fn usz TempAllocator.mark(&self) @dynamic => self.used;

-fn void! TempAllocator._free(TempAllocator* this, void* old_pointer) @local
+fn void TempAllocator.release(&self, void* old_pointer, bool) @dynamic
 {
-	// TODO fix free
-	assert((uptr)old_pointer >= (uptr)&this.data, "Pointer originates from a different allocator.");
 	usz old_size = *(usz*)(old_pointer - DEFAULT_SIZE_PREFIX);
-	if (old_pointer + old_size == &this.data[this.used])
-    {
-        this.used -= old_size;
-    }
+	if (old_pointer + old_size == &self.data[self.used])
+	{
+		self.used -= old_size;
+	}
 }
-fn void! TempAllocator._reset(TempAllocator* this, usz mark) @local
+fn void TempAllocator.reset(&self, usz mark) @dynamic
 {
-	TempAllocatorPage *last_page = this.last_page;
+	TempAllocatorPage *last_page = self.last_page;
 	while (last_page && last_page.mark > mark)
 	{
 		TempAllocatorPage *to_free = last_page;
 		last_page = last_page.prev_page;
-		this._free_page(to_free)?;
+		self._free_page(to_free)!!;
 	}
-	this.last_page = last_page;
-	this.used = mark;
+	self.last_page = last_page;
+	self.used = mark;
 }

-fn void! TempAllocator._free_page(TempAllocator* this, TempAllocatorPage* page) @inline @local
+fn void! TempAllocator._free_page(&self, TempAllocatorPage* page) @inline @local
 {
 	void* mem = page.start;
-	if (page.is_aligned()) return this.backing_allocator.free_aligned(mem);
-	return this.backing_allocator.free(mem);
+	if (page.is_aligned()) return self.backing_allocator.free_aligned(mem);
+	return self.backing_allocator.free(mem);
 }

-fn void*! TempAllocator._realloc_page(TempAllocator* this, TempAllocatorPage* page, usz size, usz alignment, usz offset) @inline @local
+fn void*! TempAllocator._realloc_page(&self, TempAllocatorPage* page, usz size, usz alignment, usz offset) @inline @local
 {
 	// Then the actual start pointer:
 	void* real_pointer = page.start;

 	// Walk backwards to find the pointer to this page.
-	TempAllocatorPage **pointer_to_prev = &this.last_page;
+	TempAllocatorPage **pointer_to_prev = &self.last_page;
 	// Remove the page from the list
 	while (*pointer_to_prev != page)
 	{
@@ -131,47 +90,56 @@ fn void*! TempAllocator._realloc_page(TempAllocator* this, TempAllocatorPage* pa
 	*pointer_to_prev = page.prev_page;
 	usz page_size = page.pagesize();
 	// Clear on size > original size.
-	void* data = this._alloc(size, alignment, offset, false)?;
+	void* data = self.acquire(size, size > page_size, alignment, offset)!;
 	mem::copy(data, &page.data[0], page_size, mem::DEFAULT_MEM_ALIGNMENT, mem::DEFAULT_MEM_ALIGNMENT);
 	if (page.is_aligned())
 	{
-		this.backing_allocator.free_aligned(real_pointer)?;
+		self.backing_allocator.free_aligned(real_pointer);
 	}
 	else
 	{
-		this.backing_allocator.free(real_pointer)?;
+		self.backing_allocator.free(real_pointer);
 	}
 	return data;
 }

-fn void*! TempAllocator._realloc(TempAllocator* this, void* pointer, usz size, usz alignment, usz offset) @inline @local
+fn void*! TempAllocator.resize(&self, void* pointer, usz size, usz alignment, usz offset) @dynamic
 {
+	if (!size)
+	{
+		self.release(pointer, alignment > 0);
+		return null;
+	}
+	if (!pointer)
+	{
+		return self.acquire(size, true, alignment, offset);
+	}
 	TempAllocatorChunk *chunk = pointer - TempAllocatorChunk.sizeof;
 	if (chunk.size == (usz)-1)
 	{
-		assert(this.last_page, "Realloc of non temp pointer");
+		assert(self.last_page, "Realloc of non temp pointer");
 		// First grab the page
 		TempAllocatorPage *page = pointer - TempAllocatorPage.sizeof;
-		return this._realloc_page(page, size, alignment, offset);
+		return self._realloc_page(page, size, alignment, offset);
 	}

 	// TODO optimize last allocation
-	TempAllocatorChunk* data = this._alloc(size, alignment, offset, size > chunk.size)?;
+	TempAllocatorChunk* data = self.acquire(size, size > chunk.size, alignment, offset)!;
 	mem::copy(data, pointer, chunk.size, mem::DEFAULT_MEM_ALIGNMENT, mem::DEFAULT_MEM_ALIGNMENT);

 	return data;
 }

 /**
- * @require math::is_power_of_2(alignment)
- * @require size > 0
+ * @require !alignment || math::is_power_of_2(alignment)
 * @require alignment <= mem::MAX_MEMORY_ALIGNMENT `alignment too big`
- * @require this != null
 **/
-fn void*! TempAllocator._alloc(TempAllocator* this, usz size, usz alignment, usz offset, bool clear) @local
+fn void*! TempAllocator.acquire(&self, usz size, bool clear, usz alignment, usz offset) @dynamic
 {
-	void* start_mem = &this.data;
-	void* starting_ptr = start_mem + this.used;
+	if (!size) return null;
+	alignment = alignment_for_allocation(alignment);
+	void* start_mem = &self.data;
+	void* starting_ptr = start_mem + self.used;
 	void* aligned_header_start = mem::aligned_pointer(starting_ptr, TempAllocatorChunk.alignof);
 	void* mem = aligned_header_start + TempAllocatorChunk.sizeof;
 	if (alignment > TempAllocatorChunk.alignof)
@@ -181,13 +149,13 @@ fn void*! TempAllocator._alloc(TempAllocator* this, usz size, usz alignment, usz
 	usz new_usage = (usz)(mem - start_mem) + size;

 	// Arena alignment, simple!
-	if (new_usage <= this.capacity)
+	if (new_usage <= self.capacity)
 	{
 		TempAllocatorChunk* chunk_start = mem - TempAllocatorChunk.sizeof;
-    	chunk_start.size = size;
-    	this.used = new_usage;
-    	if (clear) mem::clear(mem, size, mem::DEFAULT_MEM_ALIGNMENT);
-    	return mem;
+		chunk_start.size = size;
+		self.used = new_usage;
+		if (clear) mem::clear(mem, size, mem::DEFAULT_MEM_ALIGNMENT);
+		return mem;
 	}

 	// Fallback to backing allocator
@@ -198,13 +166,13 @@ fn void*! TempAllocator._alloc(TempAllocator* this, usz size, usz alignment, usz
 	{
 		// This is actually simpler, since it will create the offset for us.
 		usz total_alloc_size = TempAllocatorPage.sizeof + size;
-    	if (clear)
+		if (clear)
 		{
-			page = this.backing_allocator.calloc_aligned(total_alloc_size, alignment, TempAllocatorPage.sizeof + offset)?;
+			page = self.backing_allocator.calloc_aligned(total_alloc_size, alignment, TempAllocatorPage.sizeof + offset)!;
 		}
 		else
 		{
-			page = this.backing_allocator.alloc_aligned(total_alloc_size, alignment, TempAllocatorPage.sizeof + offset)?;
+			page = self.backing_allocator.alloc_aligned(total_alloc_size, alignment, TempAllocatorPage.sizeof + offset)!;
 		}
 		page.start = page;
 		page.size = size | PAGE_IS_ALIGNED;
@@ -214,7 +182,7 @@ fn void*! TempAllocator._alloc(TempAllocator* this, usz size, usz alignment, usz
 		// Here we might need to pad
 		usz padded_header_size = mem::aligned_offset(TempAllocatorPage.sizeof, mem::DEFAULT_MEM_ALIGNMENT);
 		usz total_alloc_size = padded_header_size + size;
-		void* alloc = (clear ? this.backing_allocator.calloc(total_alloc_size) : this.backing_allocator.alloc(total_alloc_size))?;
+		void* alloc = self.backing_allocator.acquire(total_alloc_size, clear, 0, 0)!;

 		// Find the page.
 		page = alloc + padded_header_size - TempAllocatorPage.sizeof;
@@ -227,28 +195,28 @@ fn void*! TempAllocator._alloc(TempAllocator* this, usz size, usz alignment, usz
 	// Mark it as a page
 	page.ident = ~(usz)0;
 	// Store when it was created
-	page.mark = ++this.used;
+	page.mark = ++self.used;
 	// Hook up the page.
-	page.prev_page = this.last_page;
-	this.last_page = page;
+	page.prev_page = self.last_page;
+	self.last_page = page;
 	return &page.data[0];
 }

-fn void TempAllocator.print_pages(TempAllocator* this, File f)
+fn void! TempAllocator.print_pages(&self, File* f)
 {
-	TempAllocatorPage *last_page = this.last_page;
+	TempAllocatorPage *last_page = self.last_page;
 	if (!last_page)
 	{
-		f.printf("No pages.\n");
+		io::fprintf(f, "No pages.\n")!;
 		return;
 	}
-	f.printf("---Pages----\n");
+	io::fprintf(f, "---Pages----\n")!;
 	uint index = 0;
 	while (last_page)
 	{
 		bool is_not_aligned = !(last_page.size & (1u64 << 63));
-		f.printf("%d. Alloc: %d %d at %p%s\n", ++index,
-				last_page.size & ~(1u64 << 63), last_page.mark, &last_page.data[0], is_not_aligned ? "" : " [aligned]");
+		io::fprintf(f, "%d. Alloc: %d %d at %p%s\n", ++index,
+				last_page.size & ~(1u64 << 63), last_page.mark, &last_page.data[0], is_not_aligned ? "" : " [aligned]")!;
 		last_page = last_page.prev_page;
 	}
 }
--- a/lib/std/core/allocators/tracking_allocator.c3
+++ b/lib/std/core/allocators/tracking_allocator.c3
@@ -4,102 +4,227 @@

 module std::core::mem::allocator;
 import std::collections::map;
+import std::collections::list;

-typedef PtrMap = HashMap<uptr, usz>;
+const MAX_BACKTRACE = 16;
+struct Allocation
+{
+	void* ptr;
+	usz size;
+	void*[MAX_BACKTRACE] backtrace;
+}
+
+def AllocMap = HashMap(<uptr, Allocation>);

 // A simple tracking allocator.
 // It tracks allocations using a hash map but
 // is not compatible with allocators that uses mark()
-struct TrackingAllocator
+struct TrackingAllocator (Allocator)
 {
-	inline Allocator allocator;
 	Allocator* inner_allocator;
-	PtrMap map;
+	AllocMap map;
 	usz mem_total;
 	usz allocs_total;
 }

 /**
- * Initialize a memory arena for use using the provided bytes.
+ * Initialize a tracking allocator to wrap (and track) another allocator.
 *
- * @require this != null
+ * @param [&inout] allocator "The allocator to track"
 **/
-fn void TrackingAllocator.init(TrackingAllocator* this, Allocator* allocator)
+fn void TrackingAllocator.init(&self, Allocator* allocator)
 {
-	*this = { .inner_allocator = allocator, .allocator.function = &tracking_allocator_fn };
-	this.map.init(.using = allocator);
-}
-
-fn void TrackingAllocator.free(TrackingAllocator* this)
-{
-	this.map.free();
-	*this = {};
+	*self = { .inner_allocator = allocator };
+	self.map.init_new(.allocator = allocator);
 }

 /**
- * @param [inout] data
- * @require !alignment || math::is_power_of_2(alignment)
- */
-fn void*! tracking_allocator_fn(Allocator* data, usz size, usz alignment, usz offset, void* old_pointer, AllocationKind kind) @private
+ * Free this tracking allocator.
+ **/
+fn void TrackingAllocator.free(&self)
 {
-	TrackingAllocator* this = (TrackingAllocator*)data;
-	void* result = this.inner_allocator.function(this.inner_allocator, size, alignment, offset, old_pointer, kind)?;
-	switch (kind)
-	{
-		case CALLOC:
-		case ALIGNED_CALLOC:
-		case ALLOC:
-		case ALIGNED_ALLOC:
-			this.map.set((uptr)result, size);
-			this.mem_total += size;
-			this.allocs_total++;
-			return result;
-		case REALLOC:
-		case ALIGNED_REALLOC:
-			this.map.remove((uptr)old_pointer);
-			this.map.set((uptr)result, size);
-			this.mem_total += size;
-			if (size > 0) this.allocs_total++;
-			return result;
-		case ALIGNED_FREE:
-		case FREE:
-			if (!old_pointer) return null;
-			this.map.remove((uptr)old_pointer);
-			return null;
-		case MARK:
-			// Unsupported
-			return null;
-		case RESET:
-			this.map.clear();
-			return null;
-	}
-	unreachable();
+	self.map.free();
+	*self = {};
 }

-fn usz TrackingAllocator.allocated(TrackingAllocator* this)
+/**
+ * @return "the total allocated memory not yet freed."
+ **/
+fn usz TrackingAllocator.allocated(&self)
 {
 	usz allocated = 0;
 	@pool()
 	{
-		foreach (usz allocation : this.map.value_tlist())
-		{
-			allocated += allocation;
-		}
+		foreach (&allocation : self.map.value_tlist()) allocated += allocation.size;
 	};
 	return allocated;
 }

-fn usz TrackingAllocator.total_allocated(TrackingAllocator* this)
+/**
+ * @return "the total memory allocated (freed or not)."
+ **/
+fn usz TrackingAllocator.total_allocated(&self) => self.mem_total;
+
+/**
+ * @return "the total number of allocations (freed or not)."
+ **/
+fn usz TrackingAllocator.total_allocation_count(&self) => self.allocs_total;
+
+fn Allocation[] TrackingAllocator.allocations_tlist(&self, Allocator* allocator)
 {
-	return this.mem_total;
+	return self.map.value_tlist();
 }

-fn usz TrackingAllocator.total_allocation_count(TrackingAllocator* this)
+/**
+ * @return "the number of non-freed allocations."
+ **/
+fn usz TrackingAllocator.allocation_count(&self) => self.map.count;
+
+fn void*! TrackingAllocator.acquire(&self, usz size, bool clear, usz alignment, usz offset) @dynamic
 {
-	return this.allocs_total;
+	void* data = self.inner_allocator.acquire(size, clear, alignment, offset)!;
+	self.allocs_total++;
+	if (data)
+	{
+		void*[MAX_BACKTRACE] bt;
+		backtrace::capture_current(&bt);
+		self.map.set((uptr)data, { data, size, bt });
+    	self.mem_total += size;
+		self.allocs_total++;
+	}
+	return data;
 }

-fn usz TrackingAllocator.allocation_count(TrackingAllocator* this)
+fn void*! TrackingAllocator.resize(&self, void* old_pointer, usz size, usz alignment, usz offset) @dynamic
 {
-	return this.map.count;
+	void* data = self.inner_allocator.resize(old_pointer, size, alignment, offset)!;
+	if (old_pointer)
+	{
+		self.map.remove((uptr)old_pointer);
+	}
+	if (data)
+	{
+		void*[MAX_BACKTRACE] bt;
+		backtrace::capture_current(&bt);
+		self.map.set((uptr)data, { data, size, bt });
+    	self.mem_total += size;
+		self.allocs_total++;
+	}
+	return data;
+}
+
+fn void TrackingAllocator.release(&self, void* old_pointer, bool is_aligned) @dynamic
+{
+	if (old_pointer)
+	{
+		if (catch self.map.remove((uptr)old_pointer))
+    	{
+    	    assert(false, "Attempt to release untracked pointer %p, this is likely a bug.", old_pointer);
+    	}
+	}
+	self.inner_allocator.release(old_pointer, is_aligned);
+}
+
+fn void TrackingAllocator.clear(&self)
+{
+	self.map.clear();
+}
+
+fn void TrackingAllocator.print_report(&self) => self.fprint_report(io::stdout())!!;
+
+fn void! TrackingAllocator.fprint_report(&self, OutStream* out)
+{
+
+	usz total = 0;
+	usz entries = 0;
+	bool leaks = false;
+	@pool()
+	{
+		Allocation[] allocs = self.map.value_tlist();
+		if (allocs.len)
+		{
+			if (!allocs[0].backtrace[0])
+			{
+				io::fprintn(out, "======== Memory Report ========")!;
+            	io::fprintn(out, "Size in bytes   Address")!;
+            	foreach (i, &allocation : allocs)
+            	{
+            	    entries++;
+            		total += allocation.size;
+            		io::fprintfn(out, "%13s   %p", allocation.size, allocation.ptr)!;
+            	}
+            	io::fprintn(out, "===============================")!;
+
+			}
+			else
+			{
+				io::fprintn(out, "================================== Memory Report ==================================")!;
+				io::fprintn(out, "Size in bytes   Address          Function                       ")!;
+				foreach (i, &allocation : allocs)
+				{
+					entries++;
+					total += allocation.size;
+					BacktraceList backtraces = {};
+					Backtrace trace = backtrace::BACKTRACE_UNKNOWN;
+					if (allocation.backtrace[3])
+					{
+						trace = backtrace::symbolize_backtrace(allocation.backtrace[3:1], mem::temp()).get(0) ?? backtrace::BACKTRACE_UNKNOWN;
+					}
+					if (trace.function.len)	leaks = true;
+					io::fprintfn(out, "%13s   %p   %s:%d", allocation.size,
+						allocation.ptr, trace.function.len ? trace.function : "???",
+						trace.line ? trace.line : 0)!;
+				}
+				io::fprintn(out, "===================================================================================")!;
+			}
+		}
+		else
+		{
+			io::fprintn(out, "* NO ALLOCATIONS FOUND *")!;
+		}
+		io::fprintfn(out, "- Total currently allocated memory:            %d", total)!;
+        io::fprintfn(out, "- Total current allocations:                   %d", entries)!;
+        io::fprintfn(out, "- Total allocations (freed and retained):      %d", self.allocs_total)!;
+        io::fprintfn(out, "- Total allocated memory (freed and retained): %d", self.mem_total)!;
+        if (leaks)
+        {
+			io::fprintn(out)!;
+			io::fprintn(out, "Full leak report:")!;
+            foreach (i, &allocation : allocs)
+            {
+                if (!allocation.backtrace[3])
+                {
+                    io::fprintfn(out, "Allocation %d (%d bytes) - no backtrace available.", i + 1, allocation.size)!;
+                	continue;
+				}
+                BacktraceList backtraces = {};
+                usz end = MAX_BACKTRACE;
+                foreach (j, val : allocation.backtrace)
+                {
+                    if (!val)
+                	{
+                	    end = j;
+                	    break;
+					}
+				}
+        		BacktraceList list = backtrace::symbolize_backtrace(allocation.backtrace[3..(end - 1)], mem::temp())!;
+                io::fprintfn(out, "Allocation %d (%d bytes): ", i + 1, allocation.size)!;
+        		foreach (trace : list)
+        		{
+        			if (trace.has_file())
+                	{
+                	    io::fprintfn(out, "   %s (in %s:%d)", trace.function, trace.file, trace.line);
+                	    continue;
+                	}
+                	if (trace.is_unknown())
+                	{
+                	    io::fprintfn(out, "   ??? (in unknown)");
+                	    continue;
+                	}
+					io::fprintfn(out, "   %s (source unavailable)", trace.function);
+				}
+        	}
+        }
+	};
+
 }
--- a/lib/std/core/array.c3
+++ b/lib/std/core/array.c3
@@ -1,33 +1,50 @@
 module std::core::array;

-macro tconcat(arr1, arr2)
-{
-	var $Type = $typeof(arr1[0]);
-	$Type[] result = array::talloc($Type, arr1.len + arr2.len);
-	if (arr1.len > 0)
-	{
-		mem::copy(result.ptr, &arr1[0], arr1.len * $Type.sizeof, $Type.alignof, $Type.alignof);
-	}
-	if (arr2.len > 0)
-	{
-		mem::copy(&result[arr1.len], &arr2[0], arr2.len * $Type.sizeof, $Type.alignof, $Type.alignof);
-	}
-	return result;
-}
-
+/**
+ * @param [in] array
+ * @param [in] element
+ * @return "the first index of the element"
+ * @return! SearchResult.MISSING
+ **/
 macro index_of(array, element)
 {
 	foreach (i, &e : array)
 	{
 		if (*e == element) return i;
 	}
-	return SearchResult.MISSING!;
+	return SearchResult.MISSING?;
 }

-macro concat(arr1, arr2)
+/**
+ * @param [in] array
+ * @param [in] element
+ * @return "the last index of the element"
+ * @return! SearchResult.MISSING
+ **/
+macro rindex_of(array, element)
+{
+	foreach_r (i, &e : array)
+	{
+		if (*e == element) return i;
+	}
+	return SearchResult.MISSING?;
+}
+
+/**
+ * Concatenate two arrays or subarrays, returning a subarray containing the concatenation of them.
+ *
+ * @param [in] arr1
+ * @param [in] arr2
+ * @param [&inout] allocator "The allocator to use, default is the heap allocator"
+ * @require @typekind(arr1) == SUBARRAY || @typekind(arr1) == ARRAY
+ * @require @typekind(arr2) == SUBARRAY || @typekind(arr2) == ARRAY
+ * @require @typeis(arr1[0], $typeof(arr2[0])) "Arrays must have the same type"
+ * @ensure result.len == arr1.len + arr2.len
+ **/
+macro concat_new(arr1, arr2, Allocator* allocator = mem::heap())
 {
 	var $Type = $typeof(arr1[0]);
-	$Type[] result = array::alloc($Type, arr1.len + arr2.len);
+	$Type[] result = allocator.new_array($Type, arr1.len + arr2.len);
 	if (arr1.len > 0)
 	{
 		mem::copy(result.ptr, &arr1[0], arr1.len * $Type.sizeof, $Type.alignof, $Type.alignof);
@@ -37,4 +54,17 @@ macro concat(arr1, arr2)
 		mem::copy(&result[arr1.len], &arr2[0], arr2.len * $Type.sizeof, $Type.alignof, $Type.alignof);
 	}
 	return result;
-}
+}
+
+/**
+ * Concatenate two arrays or subarrays, returning a subarray containing the concatenation of them,
+ * allocated using the temp allocator.
+ *
+ * @param [in] arr1
+ * @param [in] arr2
+ * @require @typekind(arr1) == SUBARRAY || @typekind(arr1) == ARRAY
+ * @require @typekind(arr2) == SUBARRAY || @typekind(arr2) == ARRAY
+ * @require @typeis(arr1[0], $typeof(arr2[0])) "Arrays must have the same type"
+ * @ensure result.len == arr1.len + arr2.len
+ **/
+macro tconcat(arr1, arr2) => concat(arr1, arr2, mem::temp());
--- a/lib/std/core/bitorder.c3
+++ b/lib/std/core/bitorder.c3
@@ -1,5 +1,12 @@
+// Copyright (c) 2023 Christoffer Lerno and contributors. All rights reserved.
+// Use of this source code is governed by the MIT license
+// a copy of which can be found in the LICENSE_STDLIB file.
 module std::core::bitorder;

+// This module contains types of different endianness.
+// *BE types represent big-endian types
+// *LE types represent little-endian types.
+
 bitstruct ShortBE : short @bigendian
 {
 	short val : 0..15;
@@ -80,3 +87,94 @@ bitstruct UInt128LE : uint128 @littleendian
 	uint128 val : 0..127;
 }

+/**
+ * @require is_array_or_sub_of_char(bytes) "argument must be an array, a pointer to an array or a subarray of char"
+ * @require is_bitorder($Type) "type must be a bitorder integer"
+ **/
+macro read(bytes, $Type)
+{
+	char[] s;
+	$switch (@typekind(bytes))
+	$case POINTER:
+		s = (*bytes)[:$Type.sizeof];
+	$default:
+		s = bytes[:$Type.sizeof];
+	$endswitch
+	return bitcast(*(char[$Type.sizeof]*)s.ptr, $Type).val;
+}
+
+/**
+ * @require is_arrayptr_or_sub_of_char(bytes) "argument must be a pointer to an array or a subarray of char"
+ * @require is_bitorder($Type) "type must be a bitorder integer"
+ **/
+macro write(x, bytes, $Type)
+{
+	char[] s;
+	$switch (@typekind(bytes))
+	$case POINTER:
+		s = (*bytes)[:$Type.sizeof];
+	$default:
+		s = bytes[:$Type.sizeof];
+	$endswitch
+	*($typeof(x)*)s.ptr = bitcast(x, $Type).val;
+}
+
+macro is_bitorder($Type)
+{
+	$switch ($Type)
+	$case UShortLE:
+	$case ShortLE:
+	$case UIntLE:
+	$case IntLE:
+	$case ULongLE:
+	$case LongLE:
+	$case UInt128LE:
+	$case Int128LE:
+	$case UShortBE:
+	$case ShortBE:
+	$case UIntBE:
+	$case IntBE:
+	$case ULongBE:
+	$case LongBE:
+	$case UInt128BE:
+	$case Int128BE:
+		return true;
+	$default:
+		return false;
+	$endswitch
+}
+
+macro bool is_array_or_sub_of_char(bytes)
+{
+	$switch (@typekind(bytes))
+	$case POINTER:
+		var $Inner = $typefrom($typeof(bytes).inner);
+		$if $Inner.kindof == ARRAY:
+			var $Inner2 = $typefrom($Inner.inner);
+			return $Inner2.typeid == char.typeid;
+		$endif
+	$case ARRAY:
+	$case SUBARRAY:
+		var $Inner = $typefrom($typeof(bytes).inner);
+		return $Inner.typeid == char.typeid;
+	$default:
+		return false;
+	$endswitch
+}
+
+macro bool is_arrayptr_or_sub_of_char(bytes)
+{
+	$switch (@typekind(bytes))
+	$case POINTER:
+		var $Inner = $typefrom($typeof(bytes).inner);
+		$if $Inner.kindof == ARRAY:
+			var $Inner2 = $typefrom($Inner.inner);
+			return $Inner2.typeid == char.typeid;
+		$endif
+	$case SUBARRAY:
+		var $Inner = $typefrom($typeof(bytes).inner);
+		return $Inner.typeid == char.typeid;
+	$default:
+		return false;
+	$endswitch
+}
--- a/lib/std/core/builtin.c3
+++ b/lib/std/core/builtin.c3
@@ -5,17 +5,26 @@ module std::core::builtin;
 import libc;
 import std::hash;

+/**
+ * Use `IteratorResult` when reading the end of an iterator, or accessing a result out of bounds.
+ **/
 fault IteratorResult
 {
 	NO_MORE_ELEMENT
 }

+/**
+ * Use `SearchResult` when trying to return a value from some collection but the element is missing.
+ **/
 fault SearchResult
 {
 	MISSING
 }

-fault VarCastResult
+/**
+ * Use `CastResult` when an attempt at conversion fails.
+ **/
+fault CastResult
 {
 	TYPE_MISMATCH
 }
@@ -28,127 +37,229 @@ fault VarCastResult
 **/
 macro void @scope(&variable; @body) @builtin
 {
-	var temp = variable;
-	defer variable = temp;
+	var temp = *variable;
+	defer *variable = temp;
 	@body();
 }

+/**
+ * Swap two variables
+ * @require $assignable(*b, $typeof(*a)) && $assignable(*a, $typeof(*b))
+ **/
 macro void @swap(&a, &b) @builtin
 {
-	var temp = a;
-	a = b;
-	b = temp;
+	var temp = *a;
+	*a = *b;
+	*b = temp;
 }

 /**
- * Convert a variant type to a type, returning an failure if there is a type mismatch.
+ * Convert an `any` type to a type, returning an failure if there is a type mismatch.
 *
- * @param v `the variant to convert to the given type.`
+ * @param v `the any to convert to the given type.`
 * @param $Type `the type to convert to`
- * @return `The variant.ptr converted to its type.`
+ * @return `The any.ptr converted to its type.`
+ * @ensure @typeis(return, $Type*)
+ * @return! CastResult.TYPE_MISMATCH
 **/
-macro varcast(variant v, $Type) @builtin
+macro anycast(any* v, $Type) @builtin
 {
-	if (v.type != $Type.typeid) return VarCastResult.TYPE_MISMATCH!;
+	if (v.type != $Type.typeid) return CastResult.TYPE_MISMATCH?;
 	return ($Type*)v.ptr;
 }

-struct CallstackElement
+fn bool print_backtrace(String message, int backtraces_to_ignore) @if(env::NATIVE_STACKTRACE)
 {
-	CallstackElement* prev;
-	String function;
-	String file;
-	uint line;
+	@pool()
+	{
+		void*[256] buffer;
+		void*[] backtraces = backtrace::capture_current(&buffer);
+		backtraces_to_ignore++;
+		BacktraceList! backtrace = backtrace::symbolize_backtrace(backtraces, mem::temp());
+		if (catch backtrace) return false;
+		if (backtrace.len() <= backtraces_to_ignore) return false;
+		io::eprint("\nERROR: '");
+        io::eprint(message);
+        io::eprintn("'");
+		foreach (i, &trace : backtrace)
+        {
+            if (i < backtraces_to_ignore) continue;
+            if (trace.is_unknown())
+            {
+				io::eprintn("  in ???");
+				continue;
+			}
+			if (trace.has_file())
+            {
+                io::eprintfn("  in %s (%s:%d) [%s]", trace.function, trace.file, trace.line, trace.object_file);
+                continue;
+            }
+            io::eprintfn("  in %s (source unavailable) [%s]", trace.function, trace.object_file);
+		}
+		return true;
+	};
 }
-
-fn void default_panic(String message, String file, String function, uint line)
+fn void default_panic(String message, String file, String function, uint line) @if(env::NATIVE_STACKTRACE)
 {
-	CallstackElement* stack = $$stacktrace();
-	$if ($defined(libc::stderr) && $defined(libc::fprintf))
-
-	if (stack) stack = stack.prev;
-	if (stack)
-	{
-		libc::fprintf(libc::stderr(), "\nERROR: '%.*s'\n", (int)message.len, message.ptr);
-	}
-	else
-	{
-		libc::fprintf(libc::stderr(), "\nERROR: '%.*s', function %.*s (%.*s:%d)\n",
-			(int)message.len, message.ptr, (int)function.len, function.ptr, (int)file.len, file.ptr, line);
-	}
-	while (stack)
-	{
-		libc::fprintf(libc::stderr(), "  at function %.*s (%.*s:%u)\n", (int)stack.function.len, stack.function.ptr,
-		    (int)stack.file.len, stack.file.ptr, stack.line);
-		if (stack == stack.prev) break;
-		stack = stack.prev;
-	}
+	$if $defined(io::stderr):
+	if (!print_backtrace(message, 2))
+	{
+		io::eprintfn("\nERROR: '%s', in %s (%s:%d)", message, function, file, line);
+		return;
+	}
+	$endif
+	$$trap();

+}
+fn void default_panic(String message, String file, String function, uint line) @if(!env::NATIVE_STACKTRACE)
+{
+	$if $defined(io::stderr):
+	io::eprint("\nERROR: '");
+	io::eprint(message);
+	io::eprintfn("', in %s (%s:%d)", function, file, line);
 	$endif
 	$$trap();
 }

-typedef PanicFn = fn void(String message, String file, String function, uint line);
+def PanicFn = fn void(String message, String file, String function, uint line);

 PanicFn panic = &default_panic;

-macro void unreachable($string = "Unreachable statement reached.") @builtin @noreturn
+fn void panicf(String fmt, String file, String function, uint line, args...)
 {
-	panic($string, $$FILE, $$FUNC, $$LINE);
-	$$unreachable();
-}
-
-macro bitcast(expr, $Type) @builtin
-{
-	var $size = (usz)($sizeof(expr));
-	$assert($size == $Type.sizeof, "Cannot bitcast between types of different size.");
-	$Type x @noinit;
-	mem::copy(&x, &expr, $size, $Type.alignof, $alignof(expr));
-	return x;
+	@stack_mem(512; Allocator* allocator)
+	{
+		DString s;
+		s.init_new(.allocator = allocator);
+		s.appendf(fmt, ...args);
+		panic(s.str_view(), file, function, line);
+	};
 }

 /**
- * @require $Type.kindof == TypeKind.ENUM `Only enums may be used`
+ * Marks the path as unreachable. This will panic in safe mode, and in fast will simply be assumed
+ * never happens.
+ * @param [in] string "The panic message or format string"
+ **/
+macro void unreachable(String string = "Unreachable statement reached.", ...) @builtin @noreturn
+{
+	panicf(string, $$FILE, $$FUNC, $$LINE, $vasplat());
+	$$unreachable();
+}
+
+/**
+ * Marks the path as unsupported, this is similar to unreachable.
+ * @param [in] string "The error message"
+ **/
+macro void unsupported(String string = "Unsupported function invoked") @builtin @noreturn
+{
+	panicf(string, $$FILE, $$FUNC, $$LINE, $vasplat());
+	$$unreachable();
+}
+
+macro any_make(void* ptr, typeid type) @builtin
+{
+	return $$any_make(ptr, type);
+}
+
+macro any.retype_to(&self, typeid type)
+{
+	return $$any_make(self.ptr, type);
+}
+
+macro any.as_inner(&self)
+{
+	return $$any_make(self.ptr, self.type.inner);
+}
+
+/**
+ * @param expr "the expression to cast"
+ * @param $Type "the type to cast to"
+ *
+ * @require $sizeof(expr) == $Type.sizeof  "Cannot bitcast between types of different size."
+ * @ensure @typeis(return, $Type)
+ **/
+macro bitcast(expr, $Type) @builtin
+{
+	$if $Type.alignof <= $alignof(expr):
+		return *($Type*)&expr;
+	$else
+		$Type x @noinit;
+		$$memcpy(&x, &expr, $sizeof(expr), false, $Type.alignof, $alignof(expr));
+		return x;
+	$endif
+}
+
+/**
+ * @param $Type `The type of the enum`
+ * @param [in] enum_name `The name of the enum to search for`
+ * @require $Type.kindof == ENUM `Only enums may be used`
+ * @ensure @typeis(return, $Type)
+ * @return! SearchResult.MISSING
 **/
 macro enum_by_name($Type, String enum_name) @builtin
 {
 	typeid x = $Type.typeid;
 	foreach (i, name : x.names)
 	{
-		if (str::compare(name, enum_name)) return ($Type)i;
+		if (name == enum_name) return ($Type)i;
 	}
-	return SearchResult.MISSING!;
-}
-
-macro bool @likely(bool value, $probability = 1.0) @builtin
-{
-    $if ($probability == 1.0)
-	return $$expect(value, true);
-    $else
-	return $$expect_with_probability(value, true, $probability);
-    $endif
-}
-
-macro bool @unlikely(bool value, $probability = 1.0) @builtin
-{
-    $if ($probability == 1.0)
-	return $$expect(value, false);
-    $else
-	return $$expect_with_probability(value, false, $probability);
-    $endif
+	return SearchResult.MISSING?;
 }

 /**
- * @require values::@is_int(value) || values::@is_bool(value)
- * @checked $typeof(value) a = expected
+ * Mark an expression as likely to be true
+ *
+ * @param #value "expression to be marked likely"
+ * @param $probability "in the range 0 - 1"
+ * @require $probability >= 0 && $probability <= 1.0
 **/
-macro @expect(value, expected, $probability = 1.0) @builtin
+macro bool @likely(bool #value, $probability = 1.0) @builtin
 {
-    $if ($probability == 1.0)
-	return $$expect(value, ($typeof(value))expected);
-    $else
-	return $$expect_with_probability(value, expected, $probability);
-    $endif
+    $switch
+    $case env::BUILTIN_EXPECT_IS_DISABLED:
+	return #value;
+    $case $probability == 1.0:
+	return $$expect(#value, true);
+    $default:
+	return $$expect_with_probability(#value, true, $probability);
+    $endswitch
+}
+
+/**
+ * Mark an expression as unlikely to be true
+ *
+ * @param #value "expression to be marked unlikely"
+ * @param $probability "in the range 0 - 1"
+ * @require $probability >= 0 && $probability <= 1.0
+ **/
+macro bool @unlikely(bool #value, $probability = 1.0) @builtin
+{
+    $switch
+    $case env::BUILTIN_EXPECT_IS_DISABLED:
+	return #value;
+    $case $probability == 1.0:
+	return $$expect(#value, false);
+    $default:
+	return $$expect_with_probability(#value, false, $probability);
+    $endswitch
+}
+
+/**
+ * @require values::@is_int(#value) || values::@is_bool(#value)
+ * @require $assignable(expected, $typeof(#value))
+ * @require $probability >= 0 && $probability <= 1.0
+ **/
+macro @expect(#value, expected, $probability = 1.0) @builtin
+{
+    $switch
+    $case env::BUILTIN_EXPECT_IS_DISABLED:
+	return #value == expected;
+    $case $probability == 1.0:
+	return $$expect(#value, ($typeof(#value))expected);
+    $default:
+	return $$expect_with_probability(#value, expected, $probability);
+    $endswitch
 }

 /**
@@ -170,9 +281,11 @@ enum PrefetchLocality
 * @param $locality `Locality ranging from none to extremely local`
 * @param $write `Prefetch for write, otherwise prefetch for read.`
 **/
-macro prefetch(void* ptr, PrefetchLocality $locality = VERY_NEAR, bool $write = false) @builtin
+macro @prefetch(void* ptr, PrefetchLocality $locality = VERY_NEAR, bool $write = false) @builtin
 {
-	$$prefetch(ptr, $write ? 1 : 0, $locality.ordinal);
+	$if !env::BUILTIN_PREFETCH_IS_DISABLED:
+		$$prefetch(ptr, $write ? 1 : 0, $locality.ordinal);
+	$endif
 }

 macro swizzle(v, ...) @builtin
@@ -185,14 +298,21 @@ macro swizzle2(v, v2, ...) @builtin
 	return $$swizzle2(v, v2, $vasplat());
 }

-macro bool @castable(#expr, $To) @builtin
+macro anyfault @catch(#expr) @builtin
 {
-	return $checks(($To)#expr);
+	if (catch f = #expr) return f;
+	return anyfault {};
 }

-macro bool @convertible(#expr, $To) @builtin
+macro bool @ok(#expr) @builtin
 {
-	return $checks($To x = #expr);
+	if (catch #expr) return false;
+	return true;
+}
+
+macro char[] @as_char_view(&value) @builtin
+{
+	return ((char*)value)[:$sizeof(*value)];
 }

 macro uint int.hash(int i) => i;
@@ -203,7 +323,349 @@ macro uint char.hash(char c) => c;
 macro uint ichar.hash(ichar c) => c;
 macro uint long.hash(long i) => (uint)((i >> 32) ^ i);
 macro uint ulong.hash(ulong i) => (uint)((i >> 32) ^ i);
+macro uint int128.hash(int128 i) => (uint)((i >> 96) ^ (i >> 64) ^ (i >> 32) ^ i);
+macro uint uint128.hash(uint128 i) => (uint)((i >> 96) ^ (i >> 64) ^ (i >> 32) ^ i);
 macro uint bool.hash(bool b) => (uint)b;
-macro uint typeid.hash(typeid t) => (uint)(((uptr)t >> 32) ^ (uptr)t);
+macro uint typeid.hash(typeid t) => ((ulong)(uptr)t).hash();
 macro uint String.hash(String c) => (uint)fnv32a::encode(c);
-macro uint char[].hash(char[] c) => (uint)fnv32a::encode(c);
+macro uint char[].hash(char[] c) => (uint)fnv32a::encode(c);
+macro uint void*.hash(void* ptr) => ((ulong)(uptr)ptr).hash();
+
+const MAX_FRAMEADDRESS = 128;
+/**
+ * @require n >= 0
+ **/
+macro void* get_frameaddress(int n)
+{
+	if (n > MAX_FRAMEADDRESS) return null;
+	switch (n)
+	{
+		case 0: return $$frameaddress(0);
+		case 1: return $$frameaddress(1);
+		case 2: return $$frameaddress(2);
+		case 3: return $$frameaddress(3);
+		case 4: return $$frameaddress(4);
+		case 5: return $$frameaddress(5);
+		case 6: return $$frameaddress(6);
+		case 7: return $$frameaddress(7);
+		case 8: return $$frameaddress(8);
+		case 9: return $$frameaddress(9);
+		case 10: return $$frameaddress(10);
+		case 11: return $$frameaddress(11);
+		case 12: return $$frameaddress(12);
+		case 13: return $$frameaddress(13);
+		case 14: return $$frameaddress(14);
+		case 15: return $$frameaddress(15);
+		case 16: return $$frameaddress(16);
+		case 17: return $$frameaddress(17);
+		case 18: return $$frameaddress(18);
+		case 19: return $$frameaddress(19);
+		case 20: return $$frameaddress(20);
+		case 21: return $$frameaddress(21);
+		case 22: return $$frameaddress(22);
+		case 23: return $$frameaddress(23);
+		case 24: return $$frameaddress(24);
+		case 25: return $$frameaddress(25);
+		case 26: return $$frameaddress(26);
+		case 27: return $$frameaddress(27);
+		case 28: return $$frameaddress(28);
+		case 29: return $$frameaddress(29);
+		case 30: return $$frameaddress(30);
+		case 31: return $$frameaddress(31);
+		case 32: return $$frameaddress(32);
+		case 33: return $$frameaddress(33);
+		case 34: return $$frameaddress(34);
+		case 35: return $$frameaddress(35);
+		case 36: return $$frameaddress(36);
+		case 37: return $$frameaddress(37);
+		case 38: return $$frameaddress(38);
+		case 39: return $$frameaddress(39);
+		case 40: return $$frameaddress(40);
+		case 41: return $$frameaddress(41);
+		case 42: return $$frameaddress(42);
+		case 43: return $$frameaddress(43);
+		case 44: return $$frameaddress(44);
+		case 45: return $$frameaddress(45);
+		case 46: return $$frameaddress(46);
+		case 47: return $$frameaddress(47);
+		case 48: return $$frameaddress(48);
+		case 49: return $$frameaddress(49);
+		case 50: return $$frameaddress(50);
+		case 51: return $$frameaddress(51);
+		case 52: return $$frameaddress(52);
+		case 53: return $$frameaddress(53);
+		case 54: return $$frameaddress(54);
+		case 55: return $$frameaddress(55);
+		case 56: return $$frameaddress(56);
+		case 57: return $$frameaddress(57);
+		case 58: return $$frameaddress(58);
+		case 59: return $$frameaddress(59);
+		case 60: return $$frameaddress(60);
+		case 61: return $$frameaddress(61);
+		case 62: return $$frameaddress(62);
+		case 63: return $$frameaddress(63);
+		case 64: return $$frameaddress(64);
+		case 65: return $$frameaddress(65);
+		case 66: return $$frameaddress(66);
+		case 67: return $$frameaddress(67);
+		case 68: return $$frameaddress(68);
+		case 69: return $$frameaddress(69);
+		case 70: return $$frameaddress(70);
+		case 71: return $$frameaddress(71);
+		case 72: return $$frameaddress(72);
+		case 73: return $$frameaddress(73);
+		case 74: return $$frameaddress(74);
+		case 75: return $$frameaddress(75);
+		case 76: return $$frameaddress(76);
+		case 77: return $$frameaddress(77);
+		case 78: return $$frameaddress(78);
+		case 79: return $$frameaddress(79);
+		case 80: return $$frameaddress(80);
+		case 81: return $$frameaddress(81);
+		case 82: return $$frameaddress(82);
+		case 83: return $$frameaddress(83);
+		case 84: return $$frameaddress(84);
+		case 85: return $$frameaddress(85);
+		case 86: return $$frameaddress(86);
+		case 87: return $$frameaddress(87);
+		case 88: return $$frameaddress(88);
+		case 89: return $$frameaddress(89);
+		case 90: return $$frameaddress(90);
+		case 91: return $$frameaddress(91);
+		case 92: return $$frameaddress(92);
+		case 93: return $$frameaddress(93);
+		case 94: return $$frameaddress(94);
+		case 95: return $$frameaddress(95);
+		case 96: return $$frameaddress(96);
+		case 97: return $$frameaddress(97);
+		case 98: return $$frameaddress(98);
+		case 99: return $$frameaddress(99);
+		case 100: return $$frameaddress(100);
+		case 101: return $$frameaddress(101);
+		case 102: return $$frameaddress(102);
+		case 103: return $$frameaddress(103);
+		case 104: return $$frameaddress(104);
+		case 105: return $$frameaddress(105);
+		case 106: return $$frameaddress(106);
+		case 107: return $$frameaddress(107);
+		case 108: return $$frameaddress(108);
+		case 109: return $$frameaddress(109);
+		case 110: return $$frameaddress(110);
+		case 111: return $$frameaddress(111);
+		case 112: return $$frameaddress(112);
+		case 113: return $$frameaddress(113);
+		case 114: return $$frameaddress(114);
+		case 115: return $$frameaddress(115);
+		case 116: return $$frameaddress(116);
+		case 117: return $$frameaddress(117);
+		case 118: return $$frameaddress(118);
+		case 119: return $$frameaddress(119);
+		case 120: return $$frameaddress(120);
+		case 121: return $$frameaddress(121);
+		case 122: return $$frameaddress(122);
+		case 123: return $$frameaddress(123);
+		case 124: return $$frameaddress(124);
+		case 125: return $$frameaddress(125);
+		case 126: return $$frameaddress(126);
+		case 127: return $$frameaddress(127);
+		case 128: return $$frameaddress(128);
+		default: unreachable();
+	}
+}
+
+/**
+ * @require n >= 0
+ **/
+macro void* get_returnaddress(int n)
+{
+	if (n > MAX_FRAMEADDRESS) return null;
+	switch (n)
+	{
+		case 0: return $$returnaddress(0);
+		case 1: return $$returnaddress(1);
+		case 2: return $$returnaddress(2);
+		case 3: return $$returnaddress(3);
+		case 4: return $$returnaddress(4);
+		case 5: return $$returnaddress(5);
+		case 6: return $$returnaddress(6);
+		case 7: return $$returnaddress(7);
+		case 8: return $$returnaddress(8);
+		case 9: return $$returnaddress(9);
+		case 10: return $$returnaddress(10);
+		case 11: return $$returnaddress(11);
+		case 12: return $$returnaddress(12);
+		case 13: return $$returnaddress(13);
+		case 14: return $$returnaddress(14);
+		case 15: return $$returnaddress(15);
+		case 16: return $$returnaddress(16);
+		case 17: return $$returnaddress(17);
+		case 18: return $$returnaddress(18);
+		case 19: return $$returnaddress(19);
+		case 20: return $$returnaddress(20);
+		case 21: return $$returnaddress(21);
+		case 22: return $$returnaddress(22);
+		case 23: return $$returnaddress(23);
+		case 24: return $$returnaddress(24);
+		case 25: return $$returnaddress(25);
+		case 26: return $$returnaddress(26);
+		case 27: return $$returnaddress(27);
+		case 28: return $$returnaddress(28);
+		case 29: return $$returnaddress(29);
+		case 30: return $$returnaddress(30);
+		case 31: return $$returnaddress(31);
+		case 32: return $$returnaddress(32);
+		case 33: return $$returnaddress(33);
+		case 34: return $$returnaddress(34);
+		case 35: return $$returnaddress(35);
+		case 36: return $$returnaddress(36);
+		case 37: return $$returnaddress(37);
+		case 38: return $$returnaddress(38);
+		case 39: return $$returnaddress(39);
+		case 40: return $$returnaddress(40);
+		case 41: return $$returnaddress(41);
+		case 42: return $$returnaddress(42);
+		case 43: return $$returnaddress(43);
+		case 44: return $$returnaddress(44);
+		case 45: return $$returnaddress(45);
+		case 46: return $$returnaddress(46);
+		case 47: return $$returnaddress(47);
+		case 48: return $$returnaddress(48);
+		case 49: return $$returnaddress(49);
+		case 50: return $$returnaddress(50);
+		case 51: return $$returnaddress(51);
+		case 52: return $$returnaddress(52);
+		case 53: return $$returnaddress(53);
+		case 54: return $$returnaddress(54);
+		case 55: return $$returnaddress(55);
+		case 56: return $$returnaddress(56);
+		case 57: return $$returnaddress(57);
+		case 58: return $$returnaddress(58);
+		case 59: return $$returnaddress(59);
+		case 60: return $$returnaddress(60);
+		case 61: return $$returnaddress(61);
+		case 62: return $$returnaddress(62);
+		case 63: return $$returnaddress(63);
+		case 64: return $$returnaddress(64);
+		case 65: return $$returnaddress(65);
+		case 66: return $$returnaddress(66);
+		case 67: return $$returnaddress(67);
+		case 68: return $$returnaddress(68);
+		case 69: return $$returnaddress(69);
+		case 70: return $$returnaddress(70);
+		case 71: return $$returnaddress(71);
+		case 72: return $$returnaddress(72);
+		case 73: return $$returnaddress(73);
+		case 74: return $$returnaddress(74);
+		case 75: return $$returnaddress(75);
+		case 76: return $$returnaddress(76);
+		case 77: return $$returnaddress(77);
+		case 78: return $$returnaddress(78);
+		case 79: return $$returnaddress(79);
+		case 80: return $$returnaddress(80);
+		case 81: return $$returnaddress(81);
+		case 82: return $$returnaddress(82);
+		case 83: return $$returnaddress(83);
+		case 84: return $$returnaddress(84);
+		case 85: return $$returnaddress(85);
+		case 86: return $$returnaddress(86);
+		case 87: return $$returnaddress(87);
+		case 88: return $$returnaddress(88);
+		case 89: return $$returnaddress(89);
+		case 90: return $$returnaddress(90);
+		case 91: return $$returnaddress(91);
+		case 92: return $$returnaddress(92);
+		case 93: return $$returnaddress(93);
+		case 94: return $$returnaddress(94);
+		case 95: return $$returnaddress(95);
+		case 96: return $$returnaddress(96);
+		case 97: return $$returnaddress(97);
+		case 98: return $$returnaddress(98);
+		case 99: return $$returnaddress(99);
+		case 100: return $$returnaddress(100);
+		case 101: return $$returnaddress(101);
+		case 102: return $$returnaddress(102);
+		case 103: return $$returnaddress(103);
+		case 104: return $$returnaddress(104);
+		case 105: return $$returnaddress(105);
+		case 106: return $$returnaddress(106);
+		case 107: return $$returnaddress(107);
+		case 108: return $$returnaddress(108);
+		case 109: return $$returnaddress(109);
+		case 110: return $$returnaddress(110);
+		case 111: return $$returnaddress(111);
+		case 112: return $$returnaddress(112);
+		case 113: return $$returnaddress(113);
+		case 114: return $$returnaddress(114);
+		case 115: return $$returnaddress(115);
+		case 116: return $$returnaddress(116);
+		case 117: return $$returnaddress(117);
+		case 118: return $$returnaddress(118);
+		case 119: return $$returnaddress(119);
+		case 120: return $$returnaddress(120);
+		case 121: return $$returnaddress(121);
+		case 122: return $$returnaddress(122);
+		case 123: return $$returnaddress(123);
+		case 124: return $$returnaddress(124);
+		case 125: return $$returnaddress(125);
+		case 126: return $$returnaddress(126);
+		case 127: return $$returnaddress(127);
+		case 128: return $$returnaddress(128);
+		default: unreachable();
+	}
+}
+
+module std::core::builtin @if((env::LINUX || env::DARWIN) && env::COMPILER_SAFE_MODE && env::DEBUG_SYMBOLS);
+import libc;
+
+fn void sig_panic(String message)
+{
+	default_panic(message, "???", "???", 0);
+}
+
+SignalFunction old_bus_error;
+SignalFunction old_segmentation_fault;
+
+fn void sig_bus_error(CInt i)
+{
+	$if !env::NATIVE_STACKTRACE:
+		sig_panic("Illegal memory access.");
+	$else
+		$if $defined(io::stderr):
+			if (!print_backtrace("Illegal memory access.", 1))
+			{
+				io::eprintn("\nERROR: 'Illegal memory access'.");
+			}
+		$endif
+	$endif
+	$$trap();
+}
+
+fn void sig_segmentation_fault(CInt i)
+{
+	$if !env::NATIVE_STACKTRACE:
+		sig_panic("Out of bounds memory access.");
+	$else
+		$if $defined(io::stderr):
+			if (!print_backtrace("Out of bounds memory access.", 1))
+			{
+				io::eprintn("\nERROR: Memory error without backtrace, possible stack overflow.");
+			}
+		$endif
+	$endif
+	$$trap();
+}
+
+fn void install_signal_handler(CInt signal, SignalFunction func) @local
+{
+	SignalFunction old = libc::signal(signal, func);
+	// Restore
+	if ((iptr)old > 1024) libc::signal(signal, old);
+}
+
+// Clean this up
+fn void install_signal_handlers() @init(101) @local
+{
+	install_signal_handler(libc::SIGBUS, &sig_bus_error);
+	install_signal_handler(libc::SIGSEGV, &sig_segmentation_fault);
+}
+
--- a/lib/std/core/builtin_comparison.c3
+++ b/lib/std/core/builtin_comparison.c3
@@ -8,14 +8,14 @@ module std::core::builtin;
 **/
 macro less(a, b) @builtin
 {
-$switch
+	$switch
 	$case $defined(a.less):
 		return a.less(b);
 	$case $defined(a.compare_to):
 		return a.compare_to(b) < 0;
 	$default:
 		return a < b;
-$endswitch
+	$endswitch
 }

 /**
@@ -23,14 +23,14 @@ $endswitch
 **/
 macro less_eq(a, b) @builtin
 {
-$switch
+	$switch
 	$case $defined(a.less):
 		return !b.less(a);
 	$case $defined(a.compare_to):
 		return a.compare_to(b) <= 0;
 	$default:
 		return a <= b;
-$endswitch
+	$endswitch
 }

 /**
@@ -38,29 +38,43 @@ $endswitch
 **/
 macro greater(a, b) @builtin
 {
-$switch
+	$switch
 	$case $defined(a.less):
 		return b.less(a);
 	$case $defined(a.compare_to):
 		return a.compare_to(b) > 0;
 	$default:
 		return a > b;
-$endswitch
+	$endswitch
 }

+/**
+ * @require types::is_comparable_value(a) && types::is_comparable_value(b)
+ **/
+macro int compare_to(a, b) @builtin
+{
+	$switch
+	$case $defined(a.compare_to):
+		return a.compare_to(b);
+	$case $defined(a.less):
+		return (int)b.less(a) - (int)a.less(b);
+	$default:
+		return (int)(a > b) - (int)(a < b);
+	$endswitch
+}
 /**
 * @require types::is_comparable_value(a) && types::is_comparable_value(b)
 **/
 macro greater_eq(a, b) @builtin
 {
-$switch
+	$switch
 	$case $defined(a.less):
 		return !a.less(b);
 	$case $defined(a.compare_to):
 		return a.compare_to(b) >= 0;
 	$default:
 		return a >= b;
-$endswitch
+	$endswitch
 }

 /**
@@ -68,47 +82,47 @@ $endswitch
 **/
 macro bool equals(a, b) @builtin
 {
-$switch
-	$case $defined(a.equals):
+	$switch
+	$case $defined(a.equals, a.equals(b)):
 		return a.equals(b);
-	$case $defined(a.compare_to):
+	$case $defined(a.compare_to, a.compare_to(b)):
 		return a.compare_to(b) == 0;
 	$case $defined(a.less):
 		return !a.less(b) && !b.less(a);
 	$default:
 		return a == b;
-$endswitch
+	$endswitch
 }

 macro min(x, ...) @builtin
 {
-    $if ($vacount == 1)
-        return less(x, $vaarg(0)) ? x : $vaarg(0);
-    $else
-        var result = x;
-        $for (var $i = 0; $i < $vacount; $i++)
-            if (less($vaarg($i), result))
-            {
-                 result = $vaarg($i);
-            }
-        $endfor
-        return result;
-    $endif
+	$if $vacount == 1:
+		return less(x, $vaarg(0)) ? x : $vaarg(0);
+	$else
+		var result = x;
+		$for (var $i = 0; $i < $vacount; $i++)
+			if (less($vaarg($i), result))
+			{
+				 result = $vaarg($i);
+			}
+		$endfor
+		return result;
+	$endif
 }

 macro max(x, ...) @builtin
 {
-    $if ($vacount == 1)
-        return greater(x, $vaarg(0)) ? x : $vaarg(0);
-    $else
-        var result = x;
-        $for (var $i = 0; $i < $vacount; $i++)
-            if (greater($vaarg($i), result))
-            {
-                 result = $vaarg($i);
-            }
-        $endfor
-        return result;
-    $endif
+	$if $vacount == 1:
+		return greater(x, $vaarg(0)) ? x : $vaarg(0);
+	$else
+		var result = x;
+		$for (var $i = 0; $i < $vacount; $i++)
+			if (greater($vaarg($i), result))
+			{
+				 result = $vaarg($i);
+			}
+		$endfor
+		return result;
+	$endif
 }

--- a/lib/std/core/cinterop.c3
+++ b/lib/std/core/cinterop.c3
@@ -8,80 +8,48 @@ const C_LONG_SIZE = $$C_LONG_SIZE;
 const C_SHORT_SIZE = $$C_SHORT_SIZE;
 const C_LONG_LONG_SIZE = $$C_LONG_LONG_SIZE;

-$assert (C_SHORT_SIZE < 32);
-$assert (C_INT_SIZE < 128);
-$assert (C_LONG_SIZE < 128);
-$assert (C_LONG_LONG_SIZE <= 128);
-$assert (C_SHORT_SIZE <= C_INT_SIZE);
-$assert (C_INT_SIZE <= C_LONG_SIZE);
-$assert (C_LONG_SIZE <= C_LONG_LONG_SIZE);
+$assert C_SHORT_SIZE < 32;
+$assert C_INT_SIZE < 128;
+$assert C_LONG_SIZE < 128;
+$assert C_LONG_LONG_SIZE <= 128;
+$assert C_SHORT_SIZE <= C_INT_SIZE;
+$assert C_INT_SIZE <= C_LONG_SIZE;
+$assert C_LONG_SIZE <= C_LONG_LONG_SIZE;

-$switch ($$C_INT_SIZE)
-$case 64:
-    typedef CInt = long;
-    typedef CUInt = ulong;
-$case 32:
-    typedef CInt = int;
-    typedef CUInt = uint;
-$case 16:
-    typedef CInt = short;
-    typedef CUInt = ushort;
-$default:
-    $assert(false, "Invalid C int size");
-$endswitch
+def CShort = $typefrom(signed_int_from_bitsize($$C_SHORT_SIZE));
+def CUShort = $typefrom(unsigned_int_from_bitsize($$C_SHORT_SIZE));
+def CInt = $typefrom(signed_int_from_bitsize($$C_INT_SIZE));
+def CUInt = $typefrom(unsigned_int_from_bitsize($$C_INT_SIZE));
+def CLong = $typefrom(signed_int_from_bitsize($$C_LONG_SIZE));
+def CULong = $typefrom(unsigned_int_from_bitsize($$C_LONG_SIZE));
+def CLongLong = $typefrom(signed_int_from_bitsize($$C_LONG_LONG_SIZE));
+def CULongLong = $typefrom(unsigned_int_from_bitsize($$C_LONG_LONG_SIZE));
+def CSChar = ichar;
+def CUChar = char;

-$switch ($$C_LONG_SIZE)
-$case 64:
-    typedef CLong = long;
-    typedef CULong = ulong;
-$case 32:
-    typedef CLong = int;
-    typedef CULong = uint;
-$case 16:
-    typedef CLong = short;
-    typedef CULong = ushort;
-$default:
-    $assert(false, "Invalid C long size");
-$endswitch
+def CChar = $typefrom($$C_CHAR_IS_SIGNED ? ichar.typeid : char.typeid);

-$switch ($$C_SHORT_SIZE)
-$case 32:
-    typedef CShort = int;
-    typedef CUShort = uint;
-$case 16:
-    typedef CShort = short;
-    typedef CUShort = ushort;
-$case 8:
-    typedef CShort = ichar;
-    typedef CUShort = char;
-$default:
-    $assert(false, "Invalid C short size");
-$endswitch
+// Helper macros
+macro typeid signed_int_from_bitsize(usz $bitsize) @private
+{
+	$switch ($bitsize)
+		$case 128: return int128.typeid;
+		$case 64: return long.typeid;
+		$case 32: return int.typeid;
+		$case 16: return short.typeid;
+		$case 8: return ichar.typeid;
+		$default: $error("Invalid bitsize");
+	$endswitch
+}

-$switch ($$C_LONG_LONG_SIZE)
-$case 128:
-    typedef CLongLong = int128;
-    typedef CULongLong = uint128;
-$case 64:
-    typedef CLongLong = long;
-    typedef CULongLong = ulong;
-$case 32:
-    typedef CLongLong = int;
-    typedef CULongLong = uint;
-$case 16:
-    typedef CLongLong = short;
-    typedef CULongLong = ushort;
-$default:
-    $assert(false, "Invalid C long long size");
-$endswitch
-
-
-
-typedef CSChar = ichar;
-typedef CUChar = char;
-
-$if ($$C_CHAR_IS_SIGNED)
-    typedef CChar = ichar;
-$else
-    typedef CChar = char;
-$endif
+macro typeid unsigned_int_from_bitsize(usz $bitsize) @private
+{
+	$switch ($bitsize)
+		$case 128: return uint128.typeid;
+		$case 64: return ulong.typeid;
+		$case 32: return uint.typeid;
+		$case 16: return ushort.typeid;
+		$case 8: return char.typeid;
+		$default: $error("Invalid bitsize");
+	$endswitch
+}
--- a/lib/std/core/conv.c3
+++ b/lib/std/core/conv.c3
@@ -12,37 +12,36 @@ const uint UTF16_SURROGATE_HIGH_VALUE @private = 0xD800;
 /**
 * @param c `The utf32 codepoint to convert`
 * @param [out] output `the resulting buffer`
- * @param available `the size available`
 **/
-fn usz! char32_to_utf8(Char32 c, char* output, usz available)
+fn usz! char32_to_utf8(Char32 c, char[] output)
 {
-	if (!available) return UnicodeResult.CONVERSION_FAILED!;
+	if (!output.len) return UnicodeResult.CONVERSION_FAILED?;
 	switch (true)
 	{
 		case c <= 0x7f:
 			output[0] = (char)c;
 			return 1;
 		case c <= 0x7ff:
-	        if (available < 2) return UnicodeResult.CONVERSION_FAILED!;
+			if (output.len < 2) return UnicodeResult.CONVERSION_FAILED?;
 			output[0] = (char)(0xC0 | c >> 6);
-            output[1] = (char)(0x80 | (c & 0x3F));
-            return 2;
-        case c <= 0xffff:
-	        if (available < 3) return UnicodeResult.CONVERSION_FAILED!;
-            output[0] = (char)(0xE0 | c >> 12);
-            output[1] = (char)(0x80 | (c >> 6 & 0x3F));
-            output[2] = (char)(0x80 | (c & 0x3F));
-            return 3;
-        case c <= 0x10ffff:
-	        if (available < 4) return UnicodeResult.CONVERSION_FAILED!;
-		    output[0] = (char)(0xF0 | c >> 18);
-            output[1] = (char)(0x80 | (c >> 12 & 0x3F));
-            output[2] = (char)(0x80 | (c >> 6 & 0x3F));
-            output[3] = (char)(0x80 | (c & 0x3F));
-            return 4;
-        default:
-            // 0x10FFFF and above is not defined.
-            return UnicodeResult.CONVERSION_FAILED!;
+			output[1] = (char)(0x80 | (c & 0x3F));
+			return 2;
+		case c <= 0xffff:
+			if (output.len < 3) return UnicodeResult.CONVERSION_FAILED?;
+			output[0] = (char)(0xE0 | c >> 12);
+			output[1] = (char)(0x80 | (c >> 6 & 0x3F));
+			output[2] = (char)(0x80 | (c & 0x3F));
+			return 3;
+		case c <= 0x10ffff:
+			if (output.len < 4) return UnicodeResult.CONVERSION_FAILED?;
+			output[0] = (char)(0xF0 | c >> 18);
+			output[1] = (char)(0x80 | (c >> 12 & 0x3F));
+			output[2] = (char)(0x80 | (c >> 6 & 0x3F));
+			output[3] = (char)(0x80 | (c & 0x3F));
+			return 4;
+		default:
+			// 0x10FFFF and above is not defined.
+			return UnicodeResult.CONVERSION_FAILED?;
 	}
 }

@@ -83,21 +82,21 @@ fn void! char16_to_utf8_unsafe(Char16 *ptr, usz *available, char** output)
 		*available = 1;
 		return;
 	}
-    // Low surrogate first is an error
-	if (high & UTF16_SURROGATE_MASK != UTF16_SURROGATE_HIGH_VALUE) return UnicodeResult.INVALID_UTF16!;
+	// Low surrogate first is an error
+	if (high & UTF16_SURROGATE_MASK != UTF16_SURROGATE_HIGH_VALUE) return UnicodeResult.INVALID_UTF16?;

 	// Unmatched high surrogate is an error
-	if (*available == 1) return UnicodeResult.INVALID_UTF16!;
+	if (*available == 1) return UnicodeResult.INVALID_UTF16?;

 	Char16 low = ptr[1];

 	// Unmatched high surrogate, invalid
-	if (low & UTF16_SURROGATE_MASK != UTF16_SURROGATE_LOW_VALUE) return UnicodeResult.INVALID_UTF16!;
+	if (low & UTF16_SURROGATE_MASK != UTF16_SURROGATE_LOW_VALUE) return UnicodeResult.INVALID_UTF16?;

-    // The high bits of the codepoint are the value bits of the high surrogate
-    // The low bits of the codepoint are the value bits of the low surrogate
-    Char32 uc = (high & UTF16_SURROGATE_CODEPOINT_MASK) << UTF16_SURROGATE_BITS
-                | (low & UTF16_SURROGATE_CODEPOINT_MASK) + UTF16_SURROGATE_OFFSET;
+	// The high bits of the codepoint are the value bits of the high surrogate
+	// The low bits of the codepoint are the value bits of the low surrogate
+	Char32 uc = (high & UTF16_SURROGATE_CODEPOINT_MASK) << UTF16_SURROGATE_BITS
+				| (low & UTF16_SURROGATE_CODEPOINT_MASK) + UTF16_SURROGATE_OFFSET;
 	char32_to_utf8_unsafe(uc, output);
 	*available = 2;
 }
@@ -105,24 +104,28 @@ fn void! char16_to_utf8_unsafe(Char16 *ptr, usz *available, char** output)
 * @param c `The utf32 codepoint to convert`
 * @param [inout] output `the resulting buffer`
 **/
-fn void char32_to_utf8_unsafe(Char32 c, char** output)
+fn usz char32_to_utf8_unsafe(Char32 c, char** output)
 {
-	switch (true)
+	switch
 	{
 		case c < 0x7f:
 			(*output)++[0] = (char)c;
+			return 1;
 		case c < 0x7ff:
 			(*output)++[0] = (char)(0xC0 | c >> 6);
-            (*output)++[0] = (char)(0x80 | (c & 0x3F));
-        case c < 0xffff:
-	        (*output)++[0] = (char)(0xE0 | c >> 12);
-            (*output)++[0] = (char)(0x80 | (c >> 6 & 0x3F));
-            (*output)++[0] = (char)(0x80 | (c & 0x3F));
-        default:
-	 	    (*output)++[0] = (char)(0xF0 | c >> 18);
-            (*output)++[0] = (char)(0x80 | (c >> 12 & 0x3F));
-            (*output)++[0] = (char)(0x80 | (c >> 6 & 0x3F));
-            (*output)++[0] = (char)(0x80 | (c & 0x3F));
+			(*output)++[0] = (char)(0x80 | (c & 0x3F));
+			return 2;
+		case c < 0xffff:
+			(*output)++[0] = (char)(0xE0 | c >> 12);
+			(*output)++[0] = (char)(0x80 | (c >> 6 & 0x3F));
+			(*output)++[0] = (char)(0x80 | (c & 0x3F));
+			return 3;
+		default:
+			(*output)++[0] = (char)(0xF0 | c >> 18);
+			(*output)++[0] = (char)(0x80 | (c >> 12 & 0x3F));
+			(*output)++[0] = (char)(0x80 | (c >> 6 & 0x3F));
+			(*output)++[0] = (char)(0x80 | (c & 0x3F));
+			return 4;
 	}
 }

@@ -134,50 +137,50 @@ fn void char32_to_utf8_unsafe(Char32 c, char** output)
 fn Char32! utf8_to_char32(char* ptr, usz* size)
 {
 	usz max_size = *size;
-	if (max_size < 1) return UnicodeResult.INVALID_UTF8!;
+	if (max_size < 1) return UnicodeResult.INVALID_UTF8?;
 	char c = (ptr++)[0];

-    if ((c & 0x80) == 0)
-    {
-        *size = 1;
-        return c;
-    }
-    if ((c & 0xE0) == 0xC0)
-    {
-		if (max_size < 2) return UnicodeResult.INVALID_UTF8!;
-        *size = 2;
-        Char32 uc = (c & 0x1F) << 6;
-        c = *ptr;
-        // Overlong sequence or invalid second.
-		if (!uc || c & 0xC0 != 0x80) return UnicodeResult.INVALID_UTF8!;
+	if ((c & 0x80) == 0)
+	{
+		*size = 1;
+		return c;
+	}
+	if ((c & 0xE0) == 0xC0)
+	{
+		if (max_size < 2) return UnicodeResult.INVALID_UTF8?;
+		*size = 2;
+		Char32 uc = (c & 0x1F) << 6;
+		c = *ptr;
+		// Overlong sequence or invalid second.
+		if (!uc || c & 0xC0 != 0x80) return UnicodeResult.INVALID_UTF8?;
 		return uc + c & 0x3F;
-    }
-    if ((c & 0xF0) == 0xE0)
-    {
-		if (max_size < 3) return UnicodeResult.INVALID_UTF8!;
-        *size = 3;
-        Char32 uc = (c & 0x0F) << 12;
+	}
+	if ((c & 0xF0) == 0xE0)
+	{
+		if (max_size < 3) return UnicodeResult.INVALID_UTF8?;
+		*size = 3;
+		Char32 uc = (c & 0x0F) << 12;
 		c = ptr++[0];
-		if (c & 0xC0 != 0x80) return UnicodeResult.INVALID_UTF8!;
+		if (c & 0xC0 != 0x80) return UnicodeResult.INVALID_UTF8?;
 		uc += (c & 0x3F) << 6;
 		c = ptr++[0];
 		// Overlong sequence or invalid last
-		if (!uc || c & 0xC0 != 0x80) return UnicodeResult.INVALID_UTF8!;
+		if (!uc || c & 0xC0 != 0x80) return UnicodeResult.INVALID_UTF8?;
 		return uc + c & 0x3F;
-    }
-    if (max_size < 4) return UnicodeResult.INVALID_UTF8!;
-    if ((c & 0xF8) != 0xF0) return UnicodeResult.INVALID_UTF8!;
-    *size = 4;
-    Char32 uc = (c & 0x07) << 18;
+	}
+	if (max_size < 4) return UnicodeResult.INVALID_UTF8?;
+	if ((c & 0xF8) != 0xF0) return UnicodeResult.INVALID_UTF8?;
+	*size = 4;
+	Char32 uc = (c & 0x07) << 18;
 	c = ptr++[0];
-	if (c & 0xC0 != 0x80) return UnicodeResult.INVALID_UTF8!;
+	if (c & 0xC0 != 0x80) return UnicodeResult.INVALID_UTF8?;
 	uc += (c & 0x3F) << 12;
 	c = ptr++[0];
-	if (c & 0xC0 != 0x80) return UnicodeResult.INVALID_UTF8!;
+	if (c & 0xC0 != 0x80) return UnicodeResult.INVALID_UTF8?;
 	uc += (c & 0x3F) << 6;
 	c = ptr++[0];
 	// Overlong sequence or invalid last
-	if (!uc || c & 0xC0 != 0x80) return UnicodeResult.INVALID_UTF8!;
+	if (!uc || c & 0xC0 != 0x80) return UnicodeResult.INVALID_UTF8?;
 	return uc + c & 0x3F;
 }

@@ -272,8 +275,8 @@ fn usz utf16len_for_utf8(String utf8)
 		if (c & 0xF0 == 0xE0) continue;
 		i++;
 		len16++;
-    }
-    return len16;
+	}
+	return len16;
 }

 /**
@@ -297,19 +300,17 @@ fn usz utf16len_for_utf32(Char32[] utf32)
 * @param [out] utf8_buffer
 * @return `the number of bytes written.`
 **/
-fn usz! utf32to8(Char32[] utf32, String utf8_buffer)
+fn usz! utf32to8(Char32[] utf32, char[] utf8_buffer)
 {
-	usz len = utf8_buffer.len;
-	char* ptr = utf8_buffer.ptr;
-	foreach (Char32 uc : utf32)
+	char[] buffer = utf8_buffer;
+	foreach (uc : utf32)
 	{
-		usz used = char32_to_utf8(uc, ptr, len) @inline?;
-		len -= used;
-		ptr += used;
+		usz used = char32_to_utf8(uc, buffer) @inline!;
+		buffer = buffer[used..];
 	}
 	// Zero terminate if there is space.
-    if (len > 0) ptr[0] = 0;
-	return utf8_buffer.len - len;
+	if (buffer.len > 0) buffer[0] = 0;
+	return utf8_buffer.len - buffer.len;
 }

 /**
@@ -323,19 +324,19 @@ fn usz! utf8to32(String utf8, Char32[] utf32_buffer)
 {
 	usz len = utf8.len;
 	Char32* ptr = utf32_buffer.ptr;
-    usz len32 = 0;
-    usz buf_len = utf32_buffer.len;
-    for (usz i = 0; i < len;)
-    {
-        if (len32 == buf_len) return UnicodeResult.CONVERSION_FAILED!;
-        usz width = len - i;
-    	Char32 uc = utf8_to_char32(&utf8[i], &width) @inline?;
-    	i += width;
-    	ptr[len32++] = uc;
-    }
-    // Zero terminate if possible
-    if (len32 + 1 < buf_len) ptr[len32] = 0;
-    return len32;
+	usz len32 = 0;
+	usz buf_len = utf32_buffer.len;
+	for (usz i = 0; i < len;)
+	{
+		if (len32 == buf_len) return UnicodeResult.CONVERSION_FAILED?;
+		usz width = len - i;
+		Char32 uc = utf8_to_char32(&utf8[i], &width) @inline!;
+		i += width;
+		ptr[len32++] = uc;
+	}
+	// Zero terminate if possible
+	if (len32 + 1 < buf_len) ptr[len32] = 0;
+	return len32;
 }

 /**
@@ -352,7 +353,7 @@ fn void! utf16to8_unsafe(Char16[] utf16, char* utf8_buffer)
 	for (usz i = 0; i < len16;)
 	{
 		usz available = len16 - i;
-		char16_to_utf8_unsafe(&utf16[i], &available, &utf8_buffer) @inline?;
+		char16_to_utf8_unsafe(&utf16[i], &available, &utf8_buffer) @inline!;
 		i += available;
 	}
 }
@@ -369,12 +370,12 @@ fn void! utf8to32_unsafe(String utf8, Char32* utf32_buffer)
 {
 	usz len = utf8.len;
 	for (usz i = 0; i < len;)
-    {
-        usz width = len - i;
-    	Char32 uc = utf8_to_char32(&utf8[i], &width) @inline?;
-    	i += width;
-    	(utf32_buffer++)[0] = uc;
-    }
+	{
+		usz width = len - i;
+		Char32 uc = utf8_to_char32(&utf8[i], &width) @inline!;
+		i += width;
+		(utf32_buffer++)[0] = uc;
+	}
 }

 /**
@@ -388,13 +389,13 @@ fn void! utf8to32_unsafe(String utf8, Char32* utf32_buffer)
 fn void! utf8to16_unsafe(String utf8, Char16* utf16_buffer)
 {
 	usz len = utf8.len;
-    for (usz i = 0; i < len;)
-    {
-        usz width = len - i;
-    	Char32 uc = utf8_to_char32(&utf8[i], &width) @inline?;
-        char32_to_utf16_unsafe(uc, &utf16_buffer) @inline;
-        i += width;
-    }
+	for (usz i = 0; i < len;)
+	{
+		usz width = len - i;
+		Char32 uc = utf8_to_char32(&utf8[i], &width) @inline!;
+		char32_to_utf16_unsafe(uc, &utf16_buffer) @inline;
+		i += width;
+	}
 }

 /**
--- a/lib/std/core/dstring.c3
+++ b/lib/std/core/dstring.c3
@@ -1,40 +1,43 @@
 module std::core::dstring;
+import std::io;

-typedef DString = distinct void*;
+distinct DString (OutStream) = void*;

 const usz MIN_CAPACITY @private = 16;

 /**
- * @require !str.data() "String already initialized"
+ * @require !self.data() "String already initialized"
 **/
-fn void DString.init(DString *str, usz capacity = MIN_CAPACITY, Allocator* using = mem::heap())
+fn DString DString.init_new(&self, usz capacity = MIN_CAPACITY, Allocator* allocator = mem::heap())
 {
 	if (capacity < MIN_CAPACITY) capacity = MIN_CAPACITY;
-	StringData* data = malloc(StringData, 1, .using = using, .end_padding = capacity);
-	data.allocator = using;
+	StringData* data = allocator.new(StringData, .end_padding = capacity);
+	data.allocator = allocator;
 	data.len = 0;
 	data.capacity = capacity;
-	*str = (DString)data;
+	return *self = (DString)data;
 }

 /**
- * @require !str.data() "String already initialized"
+ * @require !self.data() "String already initialized"
 **/
-fn void DString.tinit(DString *str, usz capacity = MIN_CAPACITY) => str.init(capacity, mem::temp()) @inline;
-
-fn DString new_with_capacity(usz capacity, Allocator* using = mem::heap())
+fn DString DString.init_temp(&self, usz capacity = MIN_CAPACITY)
 {
-	DString dstr;
-	dstr.init(capacity, using);
-	return dstr;
+	self.init_new(capacity, mem::temp()) @inline;
+	return *self;
 }

-fn DString tnew_with_capacity(usz capacity) => new_with_capacity(capacity, mem::temp()) @inline;
+fn DString new_with_capacity(usz capacity, Allocator* allocator = mem::heap())
+{
+	return DString{}.init_new(capacity, allocator);
+}

-fn DString new(String c = "", Allocator* using = mem::heap())
+fn DString temp_with_capacity(usz capacity) => new_with_capacity(capacity, mem::temp()) @inline;
+
+fn DString new(String c = "", Allocator* allocator = mem::heap())
 {
 	usz len = c.len;
-	StringData* data = (StringData*)new_with_capacity(len, using);
+	StringData* data = (StringData*)new_with_capacity(len, allocator);
 	if (len)
 	{
 		data.len = len;
@@ -43,26 +46,27 @@ fn DString new(String c = "", Allocator* using = mem::heap())
 	return (DString)data;
 }

-fn DString tnew(String s = "") => new(s, mem::temp()) @inline;
+fn DString temp_new(String s = "") => new(s, mem::temp()) @inline;

-fn DString DString.new_concat(DString a, DString b, Allocator* using = mem::heap())
+fn DString DString.new_concat(self, DString b, Allocator* allocator = mem::heap())
 {
 	DString string;
-	string.init(a.len() + b.len(), using);
-	string.append(a);
+	string.init_new(self.len() + b.len(), allocator);
+	string.append(self);
 	string.append(b);
 	return string;
 }

-fn DString DString.new_tconcat(DString a, DString b) => a.new_concat(b, mem::temp());
+fn DString DString.new_tconcat(self, DString b) => self.new_concat(b, mem::temp());

-fn ZString DString.zstr(DString str)
+fn ZString DString.zstr_view(&self)
 {
-	StringData* data = str.data();
+	StringData* data = self.data();
 	if (!data) return "";
 	if (data.capacity == data.len)
 	{
-		str.reserve(1);
+		self.reserve(1);
+		data = self.data();
 		data.chars[data.len] = 0;
 	}
 	else if (data.chars[data.len] != 0)
@@ -72,139 +76,116 @@ fn ZString DString.zstr(DString str)
 	return (ZString)&data.chars[0];
 }

-fn usz DString.capacity(DString this)
+fn usz DString.capacity(self)
 {
-	if (!this) return 0;
-	return this.data().capacity;
+	if (!self) return 0;
+	return self.data().capacity;
 }

-fn usz DString.len(DString this)
+fn usz DString.len(&self) @dynamic
 {
-	if (!this) return 0;
-	return this.data().len;
+	if (!*self) return 0;
+	return self.data().len;
 }

 /**
- * @require new_size <= this.len()
+ * @require new_size <= self.len()
 */
-fn void DString.chop(DString this, usz new_size)
+fn void DString.chop(self, usz new_size)
 {
-	if (!this) return;
-	this.data().len = new_size;
+	if (!self) return;
+	self.data().len = new_size;
 }

-fn String DString.str(DString str)
+fn String DString.str_view(self)
 {
-	StringData* data = (StringData*)str;
+	StringData* data = self.data();
 	if (!data) return "";
 	return (String)data.chars[:data.len];
 }

-fn void DString.append_utf32(DString* str, Char32[] chars)
+fn void DString.append_utf32(&self, Char32[] chars)
 {
-	str.reserve(chars.len);
+	self.reserve(chars.len);
 	foreach (Char32 c : chars)
 	{
-		str.append_char32(c);
+		self.append_char32(c);
 	}
 }

 /**
- * @require index < str.len()
+ * @require index < self.len()
 **/
-fn void DString.set(DString str, usz index, char c)
+fn void DString.set(self, usz index, char c)
 {
-	str.data().chars[index] = c;
+	self.data().chars[index] = c;
 }

-fn void DString.append_repeat(DString* str, char c, usz times)
+fn void DString.append_repeat(&self, char c, usz times)
 {
 	if (times == 0) return;
-	str.reserve(times);
-	StringData* data = str.data();
+	self.reserve(times);
+	StringData* data = self.data();
 	for (usz i = 0; i < times; i++)
 	{
-        data.chars[data.len++] = c;
+		data.chars[data.len++] = c;
 	}
 }

 /**
 * @require c <= 0x10ffff
 */
-fn void DString.append_char32(DString* str, Char32 c)
+fn void DString.append_char32(&self, Char32 c)
 {
-	if (c < 0x7f)
-	{
-		str.reserve(1);
-		StringData* data = str.data();
-        data.chars[data.len++] = (char)c;
-        return;
-    }
-    if (c < 0x7ff)
-    {
-		str.reserve(2);
-		StringData* data = str.data();
-		data.chars[data.len++] = (char)(0xC0 | c >> 6);
-        data.chars[data.len++] = (char)(0x80 | (c & 0x3F));
-        return;
-    }
-    if (c < 0xffff)
-    {
-		str.reserve(3);
-		StringData* data = str.data();
-		data.chars[data.len++] = (char)(0xE0 | c >> 12);
-        data.chars[data.len++] = (char)(0x80 | (c >> 6 & 0x3F));
-        data.chars[data.len++] = (char)(0x80 | (c & 0x3F));
-        return;
-    }
-	str.reserve(4);
-	StringData* data = str.data();
-	data.chars[data.len++] = (char)(0xF0 | c >> 18);
-    data.chars[data.len++] = (char)(0x80 | (c >> 12 & 0x3F));
-    data.chars[data.len++] = (char)(0x80 | (c >> 6 & 0x3F));
-    data.chars[data.len++] = (char)(0x80 | (c & 0x3F));
+	char[4] buffer @noinit;
+	char* p = &buffer;
+	usz n = conv::char32_to_utf8_unsafe(c, &p);
+	self.reserve(n);
+	StringData* data = self.data();
+	data.chars[data.len:n] = buffer[:n];
+	data.len += n;
 }

-fn DString DString.tcopy(DString* str) => str.copy(mem::temp());
+fn DString DString.tcopy(&self) => self.copy(mem::temp());

-fn DString DString.copy(DString* str, Allocator* using = null)
+fn DString DString.copy(self, Allocator* allocator = null)
 {
-	if (!str)
+	if (!self)
 	{
-		if (using) return new_with_capacity(0, using);
+		if (allocator) return new_with_capacity(0, allocator);
 		return (DString)null;
 	}
-	if (!using) using = mem::heap();
-	StringData* data = str.data();
-	DString new_string = new_with_capacity(data.capacity, using);
+	StringData* data = self.data();
+	if (!allocator) allocator = mem::heap();
+	DString new_string = new_with_capacity(data.capacity, allocator);
 	mem::copy((char*)new_string.data(), (char*)data, StringData.sizeof + data.len);
 	return new_string;
 }

-fn ZString DString.copy_zstr(DString* str, Allocator* using = mem::heap())
+fn ZString DString.copy_zstr(self, Allocator* allocator = mem::heap())
 {
-	usz str_len = str.len();
+	usz str_len = self.len();
 	if (!str_len)
 	{
-		return (ZString)calloc(1, .using = using);
+		return (ZString)allocator.calloc(1);
 	}
-	char* zstr = malloc(str_len + 1, .using = using);
-	StringData* data = str.data();
+	char* zstr = allocator.alloc(str_len + 1);
+	StringData* data = self.data();
 	mem::copy(zstr, &data.chars, str_len);
 	zstr[str_len] = 0;
 	return (ZString)zstr;
 }

-fn String DString.copy_str(DString* str, Allocator* using = mem::heap())
+fn String DString.copy_str(self, Allocator* allocator = mem::heap())
 {
-	return (String)str.copy_zstr(using)[:str.len()];
+	return (String)self.copy_zstr(allocator)[:self.len()];
 }

-fn String DString.tcopy_str(DString* str) => str.copy_str(mem::temp()) @inline;
+fn String DString.tcopy_str(self) => self.copy_str(mem::temp()) @inline;

-fn bool DString.equals(DString str, DString other_string)
+fn bool DString.equals(self, DString other_string)
 {
-	StringData *str1 = str.data();
+	StringData *str1 = self.data();
 	StringData *str2 = other_string.data();
 	if (str1 == str2) return true;
 	if (!str1) return str2.len == 0;
@@ -218,18 +199,18 @@ fn bool DString.equals(DString str, DString other_string)
 	return true;
 }

-fn void DString.free(DString* str)
+fn void DString.free(&self)
 {
-	if (!*str) return;
-	StringData* data = str.data();
+	if (!*self) return;
+	StringData* data = self.data();
 	if (!data) return;
-	free(data, .using = data.allocator);
-	*str = (DString)null;
+	data.allocator.free(data);
+	*self = (DString)null;
 }

-fn bool DString.less(DString str, DString other_string)
+fn bool DString.less(self, DString other_string)
 {
-	StringData* str1 = str.data();
+	StringData* str1 = self.data();
 	StringData* str2 = other_string.data();
 	if (str1 == str2) return false;
 	if (!str1) return str2.len != 0;
@@ -244,93 +225,167 @@ fn bool DString.less(DString str, DString other_string)
 	return true;
 }

-fn void DString.append_chars(DString* this, String str)
+fn void DString.append_chars(&self, String str)
 {
 	usz other_len = str.len;
 	if (!other_len) return;
-	if (!*this)
+	if (!*self)
 	{
-		*this = new(str);
+		*self = new(str);
 		return;
 	}
-	this.reserve(other_len);
-	StringData* data = (StringData*)*this;
+	self.reserve(other_len);
+	StringData* data = self.data();
 	mem::copy(&data.chars[data.len], str.ptr, other_len);
 	data.len += other_len;
 }

-fn Char32[] DString.copy_utf32(DString* this, Allocator* using = mem::heap())
+fn Char32[] DString.copy_utf32(&self, Allocator* allocator = mem::heap())
 {
-	return str::utf8to32(this.str(), using) @inline!!;
+	return self.str_view().to_new_utf32(allocator) @inline!!;
 }

-fn void DString.append_string(DString* this, DString str)
+fn void DString.append_string(&self, DString str)
 {
-	StringData* other = (StringData*)str;
+	StringData* other = str.data();
 	if (!other) return;
-	this.append(str.str());
+	self.append(str.str_view());
 }

-fn void DString.clear(DString* str)
+fn void DString.clear(self)
 {
-	str.data().len = 0;
+	if (!self) return;
+	self.data().len = 0;
 }

-fn void DString.append_char(DString* str, char c)
+fn usz! DString.write(&self, char[] buffer) @dynamic
 {
-	if (!*str)
+	self.append_chars((String)buffer);
+	return buffer.len;
+}
+
+fn void! DString.write_byte(&self, char c) @dynamic
+{
+	self.append_char(c);
+}
+
+fn void DString.append_char(&self, char c)
+{
+	if (!*self)
 	{
-		*str = new_with_capacity(MIN_CAPACITY);
+		*self = new_with_capacity(MIN_CAPACITY);
 	}
-	str.reserve(1);
-	StringData* data = (StringData*)*str;
+	self.reserve(1);
+	StringData* data = self.data();
 	data.chars[data.len++] = c;
 }

+/**
+ * @require start < self.len()
+ * @require end < self.len()
+ * @require end >= start "End must be same or equal to the start"
+ **/
+fn void DString.delete_range(&self, usz start, usz end)
+{
+	self.delete(start, end - start + 1);
+}

-macro void DString.append(DString* str, value)
+/**
+ * @require start < self.len()
+ * @require start + len <= self.len()
+ **/
+fn void DString.delete(&self, usz start, usz len = 1)
+{
+	if (!len) return;
+	StringData* data = self.data();
+	usz new_len = data.len - len;
+	if (new_len == 0)
+	{
+		data.len = 0;
+		return;
+	}
+	usz len_after = data.len - start - len;
+	if (len_after > 0)
+	{
+		data.chars[start:len_after] = data.chars[start + len:len_after];
+	}
+	data.len = new_len;
+}
+
+macro void DString.append(&self, value)
 {
 	var $Type = $typeof(value);
 	$switch ($Type)
 		$case char:
 		$case ichar:
-			str.append_char(value);
+			self.append_char(value);
 		$case DString:
-			str.append_string(value);
+			self.append_string(value);
 		$case String:
-			str.append_chars(value);
+			self.append_chars(value);
 		$case Char32:
-			str.append_char32(value);
+			self.append_char32(value);
 		$default:
 			$switch
-				$case @convertible(value, Char32):
-					str.append_char32(value);
-				$case @convertible(value, String):
-					str.append_chars(value);
+				$case $defined((Char32)value):
+					self.append_char32((Char32)value);
+				$case $defined((String)value):
+					self.append_chars((String)value);
 				$default:
-					$assert(false, "Unsupported type for append – use printf instead.");
+					$error "Unsupported type for append – use appendf instead.";
 			$endswitch
 	$endswitch
 }

+fn void DString.insert_at(&self, usz index, String s)
+{
+	if (s.len == 0) return;
+	self.reserve(s.len);
+	StringData* data = self.data();
+	usz len = self.len();
+	if (data.chars[:len].ptr == s.ptr)
+	{
+		// Source and destination are the same: nothing to do.
+		return;
+	}
+	index = min(index, len);
+	data.len += s.len;

-fn usz! DString.printf(DString* str, String format, args...) @maydiscard
+	char* start = data.chars[index:s.len].ptr; // area to insert into
+	mem::move(start + s.len, start, len - index); // move existing data
+	switch
+	{
+		case s.ptr <= start && start < s.ptr + s.len:
+			// Overlapping areas.
+			foreach_r (i, c : s)
+			{
+				data.chars[index + i] = c;
+			}
+		case start <= s.ptr && s.ptr < start + len:
+			// Source has moved.
+			mem::move(start, s.ptr + s.len, s.len);
+		default:
+			mem::move(start, s, s.len);
+	}
+}
+
+fn usz! DString.appendf(&self, String format, args...) @maydiscard
 {
 	Formatter formatter;
-	formatter.init(&out_string_append_fn, str);
+	formatter.init(&out_string_append_fn, self);
 	return formatter.vprintf(format, args);
 }

-fn usz! DString.printfn(DString* str, String format, args...) @maydiscard
+fn usz! DString.appendfn(&self, String format, args...) @maydiscard
 {
 	Formatter formatter;
-	formatter.init(&out_string_append_fn, str);
-	usz len = formatter.vprintf(format, args)?;
-	str.append('\n');
+	formatter.init(&out_string_append_fn, self);
+	usz len = formatter.vprintf(format, args)!;
+	self.append('\n');
 	return len + 1;
 }

-fn DString new_join(String[] s, String joiner, Allocator* using = mem::heap())
+fn DString new_join(String[] s, String joiner, Allocator* allocator = mem::heap())
 {
 	if (!s.len) return (DString)null;
 	usz total_size = joiner.len * s.len;
@@ -338,7 +393,7 @@ fn DString new_join(String[] s, String joiner, Allocator* using = mem::heap())
 	{
 		total_size += str.len;
 	}
-	DString res = new_with_capacity(total_size, using);
+	DString res = new_with_capacity(total_size, allocator);
 	res.append(s[0]);
 	foreach (String* &str : s[1..])
 	{
@@ -348,43 +403,45 @@ fn DString new_join(String[] s, String joiner, Allocator* using = mem::heap())
 	return res;
 }

-fn void! out_string_append_fn(char c, void* data) @private
+fn void! out_string_append_fn(void* data, char c) @private
 {
-	DynString* s = data;
+	DString* s = data;
 	s.append_char(c);
 }


-fn StringData* DString.data(DString str) @inline @private
+fn StringData* DString.data(self) @inline @private
 {
-	return (StringData*)str;
+	return (StringData*)self;
 }

-fn void DString.reserve(DString* str, usz addition)
+fn void DString.reserve(&self, usz addition)
 {
-	StringData* data = str.data();
+	StringData* data = self.data();
 	if (!data)
 	{
-		*str = dstring::new_with_capacity(addition);
+		*self = dstring::new_with_capacity(addition);
 		return;
 	}
 	usz len = data.len + addition;
 	if (data.capacity >= len) return;
-	usz new_capacity = data.capacity *= 2;
+	usz new_capacity = data.capacity * 2;
 	if (new_capacity < MIN_CAPACITY) new_capacity = MIN_CAPACITY;
-	*str = (DString)realloc(data, StringData.sizeof + new_capacity, .using = data.allocator);
+	while (new_capacity < len) new_capacity *= 2;
+	data.capacity = new_capacity;
+	*self = (DString)data.allocator.realloc(data, StringData.sizeof + new_capacity);
 }

-fn usz! DString.read_from_stream(DString* string, Stream* reader)
+fn usz! DString.read_from_stream(&self, InStream* reader)
 {
-	if (reader.supports_available())
+	if (&reader.available)
 	{
 		usz total_read = 0;
-		while (usz available = reader.available()?)
+		while (usz available = reader.available()!)
 		{
-			string.reserve(available);
-			StringData* data = string.data();
-			usz len = reader.read(data.chars[data.len..(data.capacity - 1)])?;
+			self.reserve(available);
+			StringData* data = self.data();
+			usz len = reader.read(data.chars[data.len..(data.capacity - 1)])!;
 			total_read += len;
 			data.len += len;
 		}
@@ -394,10 +451,10 @@ fn usz! DString.read_from_stream(DString* string, Stream* reader)
 	while (true)
 	{
 		// Reserve at least 16 bytes
-		string.reserve(16);
-		StringData* data = string.data();
+		self.reserve(16);
+		StringData* data = self.data();
 		// Read into the rest of the buffer
-		usz read = reader.read(data.chars[data.len..(data.capacity - 1)])?;
+		usz read = reader.read(data.chars[data.len..(data.capacity - 1)])!;
 		data.len += read;
 		// Ok, we reached the end.
 		if (read < 16) return total_read;
--- a/lib/std/core/env.c3
+++ b/lib/std/core/env.c3
@@ -2,13 +2,13 @@
 // Use of this source code is governed by the MIT license
 // a copy of which can be found in the LICENSE_STDLIB file.
 module std::core::env;
-import libc;
+
 enum CompilerOptLevel
 {
-    O0,
-    O1,
-    O2,
-    O3
+	O0,
+	O1,
+	O2,
+	O3
 }

 enum MemoryEnvironment
@@ -32,7 +32,7 @@ enum OsType
 	KFREEBSD,
 	LINUX,
 	PS3,
-	MACOSX,
+	MACOS,
 	NETBSD,
 	OPENBSD,
 	SOLARIS,
@@ -116,28 +116,38 @@ enum ArchType

 const OsType OS_TYPE = (OsType)$$OS_TYPE;
 const ArchType ARCH_TYPE = (ArchType)$$ARCH_TYPE;
-const bool COMPILER_LIBC_AVAILABLE = $$COMPILER_LIBC_AVAILABLE;
+const bool LIBC = $$COMPILER_LIBC_AVAILABLE;
+const bool NO_LIBC = !$$COMPILER_LIBC_AVAILABLE;
 const CompilerOptLevel COMPILER_OPT_LEVEL = (CompilerOptLevel)$$COMPILER_OPT_LEVEL;
 const bool BIG_ENDIAN = $$PLATFORM_BIG_ENDIAN;
 const bool I128_NATIVE_SUPPORT = $$PLATFORM_I128_SUPPORTED;
 const bool F16_SUPPORT = $$PLATFORM_F16_SUPPORTED;
 const bool F128_SUPPORT = $$PLATFORM_F128_SUPPORTED;
 const bool COMPILER_SAFE_MODE = $$COMPILER_SAFE_MODE;
+const bool DEBUG_SYMBOLS = $$DEBUG_SYMBOLS;
 const usz LLVM_VERSION = $$LLVM_VERSION;
 const bool BENCHMARKING = $$BENCHMARKING;
 const bool TESTING = $$TESTING;
 const MemoryEnvironment MEMORY_ENV = (MemoryEnvironment)$$MEMORY_ENVIRONMENT;
-
-macro bool os_is_win32()
-{
-	return OS_TYPE == OsType.WIN32;
-}
+const bool TRACK_MEMORY = DEBUG_SYMBOLS && (COMPILER_SAFE_MODE || TESTING);
+const bool X86_64 = ARCH_TYPE == X86_64;
+const bool AARCH64 = ARCH_TYPE == AARCH64;
+const bool NATIVE_STACKTRACE = LINUX || DARWIN || WIN32;
+const bool LINUX = LIBC && OS_TYPE == LINUX;
+const bool DARWIN = LIBC && os_is_darwin();
+const bool WIN32 = LIBC && OS_TYPE == WIN32;
+const bool POSIX = LIBC && os_is_posix();
+const bool OPENBSD = LIBC && OS_TYPE == OPENBSD;
+const bool FREEBSD = LIBC && OS_TYPE == FREEBSD;
+const bool NETBSD = LIBC && OS_TYPE == NETBSD;
+const bool WASI = LIBC && OS_TYPE == WASI;
+const bool WASM_NOLIBC @builtin = !LIBC && ARCH_TYPE == ArchType.WASM32 || ARCH_TYPE == ArchType.WASM64;

 macro bool os_is_darwin()
 {
 	$switch (OS_TYPE)
 	$case IOS:
-	$case MACOSX:
+	$case MACOS:
 	$case TVOS:
 	$case WATCHOS:
 		return true;
@@ -150,7 +160,7 @@ macro bool os_is_posix()
 {
 	$switch (OS_TYPE)
 	$case IOS:
-	$case MACOSX:
+	$case MACOS:
 	$case NETBSD:
 	$case LINUX:
 	$case KFREEBSD:
@@ -170,57 +180,5 @@ macro bool os_is_posix()
 	$endswitch
 }

-
-/**
- * @param [&in] name
- * @require name.len > 0
- **/
-fn String! get_var(String name)
-{
-$if (COMPILER_LIBC_AVAILABLE && OS_TYPE != OsType.WIN32)
-	@pool()
-	{
-		ZString val = libc::getenv(name.zstr_tcopy());
-		return val ? val.as_str() : SearchResult.MISSING!;
-	};
-$else
-	return "";
-$endif
-}
-
-
-/**
- * @param [&in] name
- * @param [&in] value
- * @require name.len > 0
- **/
-fn void set_var(String name, String value, bool overwrite = true)
-{
-$if (COMPILER_LIBC_AVAILABLE && OS_TYPE != OsType.WIN32)
-	@pool()
-	{
-		if (libc::setenv(name.zstr_tcopy(), value.zstr_copy(), (int)overwrite))
-		{
-			unreachable();
-		}
-	};
-$endif
-}
-
-/**
- * @param [&in] name
- * @require name.len > 0
- **/
-fn void clear_var(String name)
-{
-$if (COMPILER_LIBC_AVAILABLE && OS_TYPE != OsType.WIN32)
-	@pool()
-	{
-		if (libc::unsetenv(name.zstr_tcopy()))
-		{
-			unreachable();
-		}
-	};
-$endif
-}
-
+const BUILTIN_EXPECT_IS_DISABLED = $feature(DISABLE_BUILTIN_EXPECT);
+const BUILTIN_PREFETCH_IS_DISABLED = $feature(DISABLE_BUILTIN_PREFETCH);
--- a/lib/std/core/mem.c3
+++ b/lib/std/core/mem.c3
@@ -7,21 +7,172 @@ const MAX_MEMORY_ALIGNMENT = 0x1000_0000;
 const DEFAULT_MEM_ALIGNMENT = (void*.alignof) * 2;


-macro @volatile_load(&x) @builtin
+/**
+ * Load a vector from memory according to a mask assuming default alignment.
+ *
+ * @param ptr "The pointer address to load from."
+ * @param mask "The mask for the load"
+ * @param passthru "The value to use for non masked values"
+ * @require $assignable(&&passthru, $typeof(ptr)) : "Pointer and passthru must match"
+ * @require @typekind(passthru) == VECTOR : "Expected passthru to be a vector"
+ * @require passthru.len == mask.len : "Mask and passthru must have the same length"
+ *
+ * @return "A vector with the loaded values where the mask is true, passthru where the mask is false"
+ **/
+macro masked_load(ptr, bool[<*>] mask, passthru)
 {
-    return $$volatile_load(&x);
+	return $$masked_load(ptr, mask, passthru, 0);
 }

+/**
+ * Load a vector from memory according to a mask.
+ *
+ * @param ptr "The pointer address to load from."
+ * @param mask "The mask for the load"
+ * @param passthru "The value to use for non masked values"
+ * @param $alignment "The alignment to assume for the pointer"
+ *
+ * @require $assignable(&&passthru, $typeof(ptr)) : "Pointer and passthru must match"
+ * @require @typekind(passthru) == VECTOR : "Expected passthru to be a vector"
+ * @require passthru.len == mask.len : "Mask and passthru must have the same length"
+ * @require math::is_power_of_2($alignment) : "The alignment must be a power of two"
+ *
+ * @return "A vector with the loaded values where the mask is true, passthru where the mask is false"
+ **/
+macro @masked_load_aligned(ptr, bool[<*>] mask, passthru, usz $alignment)
+{
+	return $$masked_load(ptr, mask, passthru, $alignment);
+}
+
+/**
+ * Load values from a pointer vector, assuming default alignment.
+ *
+ * @param ptrvec "The vector of pointers to load from."
+ * @param mask "The mask for the load"
+ * @param passthru "The value to use for non masked values"
+ *
+ * @require @typekind(ptrvec) == VECTOR : "Expected ptrvec to be a vector"
+ * @require @typekind(passthru) == VECTOR : "Expected passthru to be a vector"
+ * @require $assignable(&&passthru[0], $typeof(ptrvec[0])) : "Pointer and passthru must match"
+ * @require passthru.len == mask.len : "Mask and passthru must have the same length"
+ * @require mask.len == ptrvec.len : "Mask and ptrvec must have the same length"
+ *
+ * @return "A vector with the loaded values where the mask is true, passthru where the mask is false"
+ **/
+macro gather(ptrvec, bool[<*>] mask, passthru)
+{
+	return $$gather(ptrvec, mask, passthru, 0);
+}
+
+
+/**
+ * Load values from a pointer vector.
+ *
+ * @param ptrvec "The vector of pointers to load from."
+ * @param mask "The mask for the load"
+ * @param passthru "The value to use for non masked values"
+ * @param $alignment "The alignment to assume for the pointers"
+ *
+ * @require @typekind(ptrvec) == VECTOR : "Expected ptrvec to be a vector"
+ * @require @typekind(passthru) == VECTOR : "Expected passthru to be a vector"
+ * @require $assignable(&&passthru[0], $typeof(ptrvec[0])) : "Pointer and passthru must match"
+ * @require passthru.len == mask.len : "Mask and passthru must have the same length"
+ * @require mask.len == ptrvec.len : "Mask and ptrvec must have the same length"
+ * @require math::is_power_of_2($alignment) : "The alignment must be a power of two"
+ *
+ * @return "A vector with the loaded values where the mask is true, passthru where the mask is false"
+ **/
+macro @gather_aligned(ptrvec, bool[<*>] mask, passthru, usz $alignment)
+{
+	return $$gather(ptrvec, mask, passthru, $alignment);
+}
+
+
+/**
+ * Store parts of a vector according to the mask, assuming default alignment.
+ *
+ * @param ptr "The pointer address to store to."
+ * @param value "The value to store masked"
+ * @param mask "The mask for the store"
+ *
+ * @require $assignable(&&value, $typeof(ptr)) : "Pointer and value must match"
+ * @require @typekind(value) == VECTOR : "Expected value to be a vector"
+ * @require value.len == mask.len : "Mask and value must have the same length"
+ **/
+macro masked_store(ptr, value, bool[<*>] mask)
+{
+	return $$masked_store(ptr, value, mask, 0);
+}
+
+/**
+ * @param ptr "The pointer address to store to."
+ * @param value "The value to store masked"
+ * @param mask "The mask for the store"
+ * @param $alignment "The alignment of the pointer"
+ *
+ * @require $assignable(&&value, $typeof(ptr)) : "Pointer and value must match"
+ * @require @typekind(value) == VECTOR : "Expected value to be a vector"
+ * @require value.len == mask.len : "Mask and value must have the same length"
+ * @require math::is_power_of_2($alignment) : "The alignment must be a power of two"
+ *
+ **/
+macro @masked_store_aligned(ptr, value, bool[<*>] mask, usz $alignment)
+{
+	return $$masked_store(ptr, value, mask, $alignment);
+}
+
+/**
+ * @param ptrvec "The vector pointer containing the addresses to store to."
+ * @param value "The value to store masked"
+ * @param mask "The mask for the store"
+ * @require @typekind(ptrvec) == VECTOR : "Expected ptrvec to be a vector"
+ * @require @typekind(value) == VECTOR : "Expected value to be a vector"
+ * @require $assignable(&&value[0], $typeof(ptrvec[0])) : "Pointer and value must match"
+ * @require value.len == mask.len : "Mask and value must have the same length"
+ * @require mask.len == ptrvec.len : "Mask and ptrvec must have the same length"
+ *
+ **/
+macro scatter(ptrvec, value, bool[<*>] mask)
+{
+	return $$scatter(ptrvec, value, mask, 0);
+}
+
+/**
+ * @param ptrvec "The vector pointer containing the addresses to store to."
+ * @param value "The value to store masked"
+ * @param mask "The mask for the store"
+ * @param $alignment "The alignment of the load"
+ *
+ * @require @typekind(ptrvec) == VECTOR : "Expected ptrvec to be a vector"
+ * @require @typekind(value) == VECTOR : "Expected value to be a vector"
+ * @require $assignable(&&value[0], $typeof(ptrvec[0])) : "Pointer and value must match"
+ * @require value.len == mask.len : "Mask and value must have the same length"
+ * @require mask.len == ptrvec.len : "Mask and ptrvec must have the same length"
+ * @require math::is_power_of_2($alignment) : "The alignment must be a power of two"
+ **/
+macro @scatter_aligned(ptrvec, value, bool[<*>] mask, usz $alignment)
+{
+	return $$scatter(ptrvec, value, mask, $alignment);
+}
+
+macro @volatile_load(&x) @builtin
+{
+	return $$volatile_load(x);
+}
+
+/**
+ * @require $assignable(y, $typeof(*x)) : "The value doesn't match the variable"
+ **/
 macro @volatile_store(&x, y) @builtin
 {
-    return $$volatile_store(&x, ($typeof(x))y);
+	return $$volatile_store(x, ($typeof(*x))y);
 }

 enum AtomicOrdering : int
 {
 	NOT_ATOMIC,         // Not atomic
 	UNORDERED,          // No lock
-	MONOTONIC,          // Consistent ordering
+	RELAXED,            // Consistent ordering
 	ACQUIRE,            // Barrier locking load/store
 	RELEASE,            // Barrier releasing load/store
 	ACQUIRE_RELEASE,    // Barrier fence to load/store
@@ -37,10 +188,11 @@ enum AtomicOrdering : int
 * @require $ordering != AtomicOrdering.RELEASE "Release ordering is not valid for load."
 * @require $ordering != AtomicOrdering.ACQUIRE_RELEASE "Acquire release is not valid for load."
 * @require types::may_load_atomic($typeof(x)) "Only integer, float and pointers may be used."
+ * @require @typekind(x) == POINTER "You can only load from a pointer"
 **/
 macro @atomic_load(&x, AtomicOrdering $ordering = SEQ_CONSISTENT, $volatile = false) @builtin
 {
-	return $$atomic_load(&x, $volatile, (int)$ordering);
+	return $$atomic_load(x, $volatile, (int)$ordering);
 }

 /**
@@ -55,14 +207,22 @@ macro @atomic_load(&x, AtomicOrdering $ordering = SEQ_CONSISTENT, $volatile = fa
 **/
 macro void @atomic_store(&x, value, AtomicOrdering $ordering = SEQ_CONSISTENT, $volatile = false) @builtin
 {
-	$$atomic_store(&x, value, $volatile, (int)$ordering);
+	$$atomic_store(x, value, $volatile, (int)$ordering);
 }

+/**
+ * @require $success != AtomicOrdering.NOT_ATOMIC && $success != AtomicOrdering.UNORDERED "Acquire ordering is not valid."
+ * @require $failure != AtomicOrdering.RELEASE && $failure != AtomicOrdering.ACQUIRE_RELEASE "Acquire release is not valid."
+ **/
 macro compare_exchange(ptr, compare, value, AtomicOrdering $success = SEQ_CONSISTENT, AtomicOrdering $failure = SEQ_CONSISTENT, bool $volatile = true, bool $weak = false, usz $alignment = 0)
 {
 	return $$compare_exchange(ptr, compare, value, $volatile, $weak, $success.ordinal, $failure.ordinal, $alignment);
 }

+/**
+ * @require $success != AtomicOrdering.NOT_ATOMIC && $success != AtomicOrdering.UNORDERED "Acquire ordering is not valid."
+ * @require $failure != AtomicOrdering.RELEASE && $failure != AtomicOrdering.ACQUIRE_RELEASE "Acquire release is not valid."
+ **/
 macro compare_exchange_volatile(ptr, compare, value, AtomicOrdering $success = SEQ_CONSISTENT, AtomicOrdering $failure = SEQ_CONSISTENT)
 {
 	return compare_exchange(ptr, compare, value, $success, $failure, true);
@@ -91,30 +251,65 @@ fn bool ptr_is_aligned(void* ptr, usz alignment) @inline

 macro void clear(void* dst, usz len, usz $dst_align = 0, bool $is_volatile = false, bool $inlined = false)
 {
-	$if ($inlined)
+	$if $inlined:
 		$$memset_inline(dst, (char)0, len, $is_volatile, $dst_align);
 	$else
 		$$memset(dst, (char)0, len, $is_volatile, $dst_align);
 	$endif
 }

+/**
+ * Copy memory from src to dst efficiently, assuming the memory ranges do not overlap.
+ *
+ * @param [&out] dst "The destination to copy to"
+ * @param [&in] src "The source to copy from"
+ * @param len "The number of bytes to copy"
+ * @param $dst_align "the alignment of the destination if different from the default, 0 assumes the default"
+ * @param $src_align "the alignment of the destination if different from the default, 0 assumes the default"
+ * @param $is_volatile "True if this copy should be treated as volatile, i.e. it can't be optimized away."
+ * @param $inlined "True if this copy should never call the OS memcpy."
+ *
+ * @require len == 0 || dst + len <= src || src + len <= dst : "Ranges may not overlap"
+ **/
 macro void copy(void* dst, void* src, usz len, usz $dst_align = 0, usz $src_align = 0, bool $is_volatile = false, bool $inlined = false)
 {
-	$if ($inlined)
+	$if $inlined:
 		$$memcpy_inline(dst, src, len, $is_volatile, $dst_align, $src_align);
 	$else
 		$$memcpy(dst, src, len, $is_volatile, $dst_align, $src_align);
 	$endif
 }

+/**
+ * Copy memory from src to dst but correctly handle the possibility of overlapping ranges.
+ *
+ * @param [&out] dst "The destination to copy to"
+ * @param [&in] src "The source to copy from"
+ * @param len "The number of bytes to copy"
+ * @param $dst_align "the alignment of the destination if different from the default, 0 assumes the default"
+ * @param $src_align "the alignment of the destination if different from the default, 0 assumes the default"
+ * @param $is_volatile "True if this copy should be treated as volatile, i.e. it can't be optimized away."
+ **/
 macro void move(void* dst, void* src, usz len, usz $dst_align = 0, usz $src_align = 0, bool $is_volatile = false)
 {
 	$$memmove(dst, src, len, $is_volatile, $dst_align, $src_align);
 }

+/**
+ * Sets all memory in a region to that of the provided byte.
+ *
+ * @param [&out] dst "The destination to copy to"
+ * @param val "The value to copy into memory"
+ * @param len "The number of bytes to copy"
+ * @param $dst_align "the alignment of the destination if different from the default, 0 assumes the default"
+ * @param $is_volatile "True if this copy should be treated as volatile, i.e. it can't be optimized away."
+ * @param $inlined "True if this copy should never call the OS memset."
+ *
+ * @ensure !len || (dst[0] == val && dst[len - 1] == val)
+ **/
 macro void set(void* dst, char val, usz len, usz $dst_align = 0, bool $is_volatile = false, bool $inlined = false)
 {
-	$if ($inlined)
+	$if $inlined:
 		$$memset_inline(dst, val, len, $is_volatile, $dst_align);
 	$else
 		$$memset(dst, val, len, $is_volatile, $dst_align);
@@ -126,16 +321,16 @@ macro void set(void* dst, char val, usz len, usz $dst_align = 0, bool $is_volati
 * @require values::@inner_kind(b) == TypeKind.SUBARRAY || values::@inner_kind(b) == TypeKind.POINTER
 * @require values::@inner_kind(a) != TypeKind.SUBARRAY || len == -1
 * @require values::@inner_kind(a) != TypeKind.POINTER || len > -1
- * @checked (a = b), (b = a)
+ * @require values::@assign_to(a, b) && values::@assign_to(b, a)
 **/
 macro bool equals(a, b, isz len = -1, usz $align = 0)
 {
-	$if (!$align)
+	$if !$align:
 		$align = $typeof(a[0]).alignof;
 	$endif
 	void* x @noinit;
 	void* y @noinit;
-	$if (values::@inner_kind(a) == TypeKind.SUBARRAY)
+	$if values::@inner_kind(a) == TypeKind.SUBARRAY:
 		len = a.len;
 		if (len != b.len) return false;
 		x = a.ptr;
@@ -148,7 +343,7 @@ macro bool equals(a, b, isz len = -1, usz $align = 0)

 	if (!len) return true;
 	var $Type;
-    $switch ($align)
+	$switch ($align)
 		$case 1:
 			$Type = char;
 		$case 2:
@@ -173,243 +368,122 @@ macro bool equals(a, b, isz len = -1, usz $align = 0)
 	return true;
 }

-macro @clone(&value) @builtin
-{
-	$typeof(value)* x = malloc($typeof(value));
-	*x = value;
-	return x;
-}
-
-macro @tclone(&value) @builtin
-{
-	$typeof(value)* x = talloc($typeof(value));
-	*x = value;
-	return x;
-}

 macro type_alloc_must_be_aligned($Type)
 {
 	return $Type.alignof > DEFAULT_MEM_ALIGNMENT;
 }
-/**
- * @require $vacount > 0 && $vacount < 3 "Expected size, type, or type + len"
- * @require $vacount != 2 || $checks($vatype(0).sizeof) "Expected 'malloc(Foo, 12)'"
- **/
-macro malloc(..., Allocator* using = mem::heap(), usz end_padding = 0) @builtin
-{
-	return malloc_checked($vasplat(), .using = using, .end_padding = end_padding)!!;
-}
-
-/**
- * @require $vacount > 0 && $vacount < 3 "Expected size, type, or type + len"
- * @require $vacount != 2 || $checks($vatype(0).sizeof) "Expected 'malloc(Foo, 12)'"
- **/
-macro malloc_checked(..., Allocator* using = mem::heap(), usz end_padding = 0) @builtin
-{
-	$if ($checks($vatype(0).sizeof))
-		var $Type = $vatype(0);
-		$assert(!type_alloc_must_be_aligned($vatype(0)),  "Type must be allocated with malloc_aligned");
-		$if ($vacount == 2)
-			usz size = $vaarg(1);
-			return (($Type*)using.alloc($Type.sizeof * size + end_padding))[:size];
-		$else
-			return ($Type*)using.alloc($Type.sizeof + end_padding);
-		$endif
-	$else
-		return using.alloc($vaarg(0) + end_padding);
-	$endif
-}
-
-
-/**
- * @require $vacount > 0 && $vacount < 3 "Expected size, type, or type + len"
- * @require $vacount != 2 || $checks($vatype(0).sizeof) "Expected 'malloc(Foo, 12)'"
- * @require alignment && math::is_power_of_2(alignment)
- **/
-macro malloc_aligned(..., usz alignment = 0, usz end_padding = 0, Allocator* using = mem::heap()) @builtin
-{
-	$if ($checks($vatype(0).sizeof))
-		var $Type = $vatype(0);
-		$if ($vacount == 2)
-			usz size = $vaarg(1);
-			return (($Type*)using.alloc_aligned($Type.sizeof * size + end_padding, alignment))[:size];
-		$else
-			return ($Type*)using.alloc_aligned($Type.sizeof + end_padding, alignment);
-		$endif
-	$else
-		return using.alloc_aligned($vaarg(0) + end_padding, alignment);
-	$endif
-}
-
-macro alloc($Type) @deprecated => malloc($Type);
-
-macro char[] alloc_bytes(usz bytes) @deprecated => malloc(char, bytes);
-
-/**
- * @require $vacount > 0 && $vacount < 3 "Expected size, type, or type + len"
- * @require $vacount != 2 || $checks($vatype(0).sizeof) "Expected 'malloc(Foo, 12)'"
- **/
-macro calloc(..., Allocator* using = mem::heap(), usz end_padding = 0) @builtin
-{
-	return calloc_checked($vasplat(), .using = using, .end_padding = end_padding)!!;
-}
-
-/**
- * @require $vacount > 0 && $vacount < 3 "Expected size, type, or type + len"
- * @require $vacount != 2 || $checks($vatype(0).sizeof) "Expected 'malloc(Foo, 12)'"
- **/
-macro calloc_checked(..., Allocator* using = mem::heap(), usz end_padding = 0) @builtin
-{
-	$if ($checks($vatype(0).sizeof))
-		var $Type = $vatype(0);
-		$assert(!type_alloc_must_be_aligned($vatype(0)),  "Type must be allocated with calloc_aligned");
-		$if ($vacount == 2)
-			usz size = $vaarg(1);
-			return (($Type*)using.calloc($Type.sizeof * size + end_padding))[:size];
-		$else
-			return ($Type*)using.calloc($Type.sizeof + end_padding);
-		$endif
-	$else
-		return using.calloc($vaarg(0) + end_padding);
-	$endif
-}
-
-
-/**
- * @require $vacount > 0 && $vacount < 3 "Expected size, type, or type + len"
- * @require $vacount != 2 || $checks($vatype(0).sizeof) "Expected 'malloc(Foo, 12)'"
- * @require alignment && math::is_power_of_2(alignment)
- **/
-macro calloc_aligned(..., usz alignment = 0, Allocator* using = mem::heap(), usz end_padding = 0) @builtin
-{
-	$if ($checks($vatype(0).sizeof))
-		var $Type = $vatype(0);
-		$if ($vacount == 2)
-			usz size = $vaarg(1);
-			return (($Type*)using.calloc_aligned($Type.sizeof * size + end_padding, alignment))[:size];
-		$else
-			return ($Type*)using.calloc_aligned($Type.sizeof + end_padding, alignment);
-		$endif
-	$else
-		return using.calloc_aligned($vaarg(0) + end_padding, alignment);
-	$endif
-}
-
-fn void* realloc(void *ptr, usz new_size, Allocator* using = mem::heap()) @builtin @inline
-{
-	return using.realloc(ptr, new_size)!!;
-}
-
-fn void*! realloc_checked(void *ptr, usz new_size, Allocator* using = mem::heap()) @builtin @inline
-{
-	return using.realloc(ptr, new_size);
-}
-
-/**
- * @require alignment && math::is_power_of_2(alignment)
- */
-fn void*! realloc_aligned(void *ptr, usz new_size, usz alignment, Allocator* using = mem::heap()) @builtin @inline
-{
-	return using.realloc_aligned(ptr, new_size, alignment);
-}
-
-macro void free(void* ptr, Allocator* using = mem::heap()) @builtin => using.free(ptr)!!;
-macro void! free_checked(void* ptr, Allocator* using = mem::heap()) @builtin => using.free(ptr);
-macro void free_aligned(void* ptr, Allocator* using = mem::heap()) @builtin => using.free_aligned(ptr)!!;
-macro void! free_aligned_checked(void* ptr, Allocator* using = mem::heap()) @builtin => using.free_aligned(ptr);

 /**
 * Run with a specific allocator inside of the macro body.
 **/
-macro void @scoped(Allocator* using; @body())
+macro void @scoped(Allocator* allocator; @body())
 {
 	Allocator* old_allocator = thread_allocator;
-	thread_allocator = using;
+	thread_allocator = allocator;
 	defer thread_allocator = old_allocator;
 	@body();
 }

-macro talloc($Type) @builtin @deprecated => tmalloc($Type);
-
-/**
- * @require $vacount > 0 && $vacount < 3 "Expected size, type, or type + len"
- * @require $vacount != 2 || $checks($vatype(0).sizeof) "Expected 'malloc(Foo, 12)'"
- **/
-macro tmalloc(..., usz end_padding = 0, usz alignment = DEFAULT_MEM_ALIGNMENT) @builtin
+macro void @report_heap_allocs_in_scope(;@body())
 {
-	$if ($checks($vatype(0).sizeof))
-		var $Type = $vatype(0);
-		$if ($vacount == 2)
-			usz size = $vaarg(1);
-			return (($Type*)temp().alloc_aligned($Type.sizeof * size + end_padding, alignment))[:size]!!;
-		$else
-			return ($Type*)temp().alloc_aligned($Type.sizeof + end_padding, alignment)!!;
-		$endif
-	$else
-		return temp().alloc_aligned($vaarg(0) + end_padding, alignment)!!;
-	$endif
-}
-
-/**
- * @require $vacount > 0 && $vacount < 3 "Expected size, type, or type + len"
- * @require $vacount != 2 || $checks($vatype(0).sizeof) "Expected 'malloc(Foo, 12)'"
- **/
-macro tcalloc(..., usz end_padding = 0, usz alignment = mem::DEFAULT_MEM_ALIGNMENT) @builtin
-{
-	$if ($checks($vatype(0).sizeof))
-		var $Type = $vatype(0);
-		$if ($vacount == 2)
-			usz size = $vaarg(1);
-			return (($Type*)temp().calloc_aligned($Type.sizeof * size + end_padding, alignment))[:size]!!;
-		$else
-			return ($Type*)temp().calloc_aligned($Type.sizeof + end_padding, alignment)!!;
-		$endif
-	$else
-		return temp().calloc_aligned($vaarg(0) + end_padding, alignment)!!;
-	$endif
-}
-
-fn void* trealloc(void* ptr, usz size, usz alignment = mem::DEFAULT_MEM_ALIGNMENT) @builtin @inline
-{
-	return temp().realloc_aligned(ptr, size, alignment)!!;
-}
-
-macro void @pool(;@body) @builtin
-{
-	TempAllocator* allocator = temp();
-	usz mark = allocator.used;
-	defer allocator.reset(mark);
+	TrackingAllocator tracker;
+	tracker.init(thread_allocator);
+	Allocator* old_allocator = thread_allocator;
+	thread_allocator = &tracker;
+	defer
+	{
+		thread_allocator = old_allocator;
+		tracker.print_report();
+		tracker.free();
+	}
 	@body();
 }

-macro void @allocating_pool(Allocator* using; @body(bool is_temp)) @builtin
+macro void @stack_mem(usz $size; @body(Allocator* mem)) @builtin
 {
-	TempAllocator* allocator = temp();
-	usz mark = allocator.used;
-	bool is_temp = allocator == using;
-	defer if (!is_temp) allocator.reset(mark);
-	@body(is_temp);
+	char[$size] buffer;
+	OnStackAllocator allocator;
+	allocator.init(&buffer, mem::heap());
+	defer allocator.free();
+	@body(&allocator);
 }

-tlocal Allocator* thread_allocator @private = allocator::LIBC_ALLOCATOR;
-tlocal TempAllocator* thread_temp_allocator @private = null;
+macro void @stack_pool(usz $size; @body) @builtin
+{
+	char[$size] buffer;
+	OnStackAllocator allocator;
+	allocator.init(&buffer, mem::heap());
+	defer allocator.free();
+	mem::@scoped(&allocator)
+	{
+		@body();
+	};
+}

-macro TempAllocator* temp_allocator() => temp();
+macro void @pool(TempAllocator* #other_temp = null; @body) @builtin
+{
+	TempAllocator* current = temp();
+	var $has_arg = !$is_const(#other_temp);
+	$if $has_arg:
+		TempAllocator* original = current;
+		if (current == (void*)#other_temp) current = temp_allocator_next();
+	$endif
+	usz mark = current.used;
+	defer
+	{
+		current.reset(mark);
+		$if $has_arg:
+			thread_temp_allocator = original;
+		$endif;
+	}
+	@body();
+}
+
+tlocal Allocator* thread_allocator @private = &allocator::LIBC_ALLOCATOR;
+tlocal TempAllocator* thread_temp_allocator @private = null;
+tlocal TempAllocator*[2] temp_allocator_pair @private;
+Allocator* temp_base_allocator @private = &allocator::LIBC_ALLOCATOR;
+
+macro TempAllocator* create_default_sized_temp_allocator(Allocator* allocator) @local
+{
+	$switch (env::MEMORY_ENV)
+	$case NORMAL:
+		return allocator::new_temp(1024 * 256, allocator)!!;
+	$case SMALL:
+		return allocator::new_temp(1024 * 16, allocator)!!;
+	$case TINY:
+		return allocator::new_temp(1024 * 2, allocator)!!;
+	$case NONE:
+		unreachable("Temp allocator must explicitly created when memory-env is set to 'none'.");
+	$endswitch
+}
+
+fn TempAllocator *temp_allocator_next() @private
+{
+	if (!thread_temp_allocator)
+	{
+		init_default_temp_allocators();
+		return thread_temp_allocator;
+	}
+	usz index = thread_temp_allocator == temp_allocator_pair[0] ? 1 : 0;
+	return thread_temp_allocator = temp_allocator_pair[index];
+}
+
+import libc;
+
+fn void init_default_temp_allocators() @private
+{
+	temp_allocator_pair[0] = create_default_sized_temp_allocator(temp_base_allocator);
+	temp_allocator_pair[1] = create_default_sized_temp_allocator(temp_base_allocator);
+	thread_temp_allocator = temp_allocator_pair[0];
+}

 macro TempAllocator* temp()
 {
 	if (!thread_temp_allocator)
 	{
-		$switch (env::MEMORY_ENV)
-		$case NORMAL:
-			thread_temp_allocator = allocator::new_temp(1024 * 256, thread_allocator)!!;
-		$case SMALL:
-			thread_temp_allocator = allocator::new_temp(1024 * 16, thread_allocator)!!;
-		$case TINY:
-			thread_temp_allocator = allocator::new_temp(1024 * 2, thread_allocator)!!;
-		$case NONE:
-			unreachable("Temp allocator must explicitly created when memory-env is set to 'none'.");
-		$endswitch
+		init_default_temp_allocators();
 	}
 	return thread_temp_allocator;
 }
@@ -417,21 +491,117 @@ macro TempAllocator* temp()
 macro Allocator* current_allocator() => thread_allocator;
 macro Allocator* heap() => thread_allocator;

-$if (!env::COMPILER_LIBC_AVAILABLE && env::ARCH_TYPE == ArchType.WASM32 || env::ARCH_TYPE == ArchType.WASM64)
+
+module std::core::mem @if(WASM_NOLIBC);

 SimpleHeapAllocator wasm_allocator @private;
-
 extern int __heap_base;

-static initialize @priority(1)
+fn void initialize_wasm_mem() @init(1) @private
 {
 	allocator::wasm_memory.allocate_block(mem::DEFAULT_MEM_ALIGNMENT)!!; // Give us a valid null.
 	// Check if we need to move the heap.
 	uptr start = (uptr)&__heap_base;
 	if (start > mem::DEFAULT_MEM_ALIGNMENT) allocator::wasm_memory.use = start;
 	wasm_allocator.init(fn (x) => allocator::wasm_memory.allocate_block(x));
+	temp_base_allocator = &wasm_allocator;
 	thread_allocator = &wasm_allocator;
 }
-$endif
+
+module std::core::mem;


+macro TrackingEnv* get_tracking_env()
+{
+	$if env::TRACK_MEMORY:
+		return &&TrackingEnv { $$FILE, $$FUNC, $$LINE };
+	$else
+		return null;
+	$endif
+}
+
+macro @clone(value) @builtin
+{
+	return mem::heap().clone(value);
+}
+
+macro @tclone(value) @builtin
+{
+	return mem::temp().clone(value);
+}
+
+fn void* malloc(usz size) @builtin @inline
+{
+	return mem::heap().alloc(size);
+}
+
+fn void* tmalloc(usz size, usz alignment = 0, usz offset = 0) @builtin @inline
+{
+	return temp().acquire(size, false, alignment, offset)!!;
+}
+
+macro new($Type)
+{
+	return heap().new($Type);
+}
+
+macro new_clear($Type)
+{
+	return heap().new_clear($Type);
+}
+
+macro new_temp($Type)
+{
+	return tmalloc($Type.sizeof);
+}
+
+macro new_temp_clear($Type)
+{
+	return tcalloc($Type.sizeof);
+}
+
+macro new_array($Type, usz elements)
+{
+	return heap().new_array($Type, elements);
+}
+
+macro temp_array($Type, usz elements)
+{
+	return (($Type*)tmalloc($Type.sizeof * elements, $Type.alignof))[:elements];
+}
+
+macro new_zero_array($Type, usz elements)
+{
+	return heap().new_zero_array($Type, elements);
+}
+
+macro temp_zero_array($Type, usz elements)
+{
+	return (($Type*)tcalloc($Type.sizeof * elements, $Type.alignof))[:elements];
+}
+
+fn void* calloc(usz size) @builtin @inline
+{
+	return heap().calloc(size);
+}
+
+fn void* tcalloc(usz size, usz alignment = 0, usz offset = 0) @builtin @inline
+{
+	return temp().acquire(size, false, alignment, offset)!!;
+}
+
+fn void* realloc(void *ptr, usz new_size) @builtin @inline
+{
+	return heap().realloc(ptr, new_size);
+}
+
+fn void free(void* ptr) @builtin @inline
+{
+	heap().free(ptr);
+}
+
+fn void* trealloc(void* ptr, usz size, usz alignment = mem::DEFAULT_MEM_ALIGNMENT) @builtin @inline
+{
+	return temp().resize(ptr, size, alignment, 0)!!;
+}
+
--- a/lib/std/core/mem_allocator.c3
+++ b/lib/std/core/mem_allocator.c3
@@ -3,107 +3,222 @@ module std::core::mem::allocator;
 const DEFAULT_SIZE_PREFIX = usz.sizeof;
 const DEFAULT_SIZE_PREFIX_ALIGNMENT = usz.alignof;

-const Allocator* NULL_ALLOCATOR = &_NULL_ALLOCATOR;
-const Allocator* LIBC_ALLOCATOR = &_SYSTEM_ALLOCATOR;
-
-typedef AllocatorFunction = fn void*!(Allocator* allocator, usz new_size, usz alignment, usz offset, void* old_pointer, AllocationKind kind);
-
-struct Allocator
+struct TrackingEnv
 {
-    AllocatorFunction function;
+	String file;
+	String function;
+	uint line;
 }

-enum AllocationKind
+
+interface Allocator
 {
-    ALLOC,
-    CALLOC,
-    REALLOC,
-    FREE,
-    ALIGNED_ALLOC,
-    ALIGNED_CALLOC,
-    ALIGNED_REALLOC,
-    ALIGNED_FREE,
-    RESET,
-    MARK,
+	fn void reset(usz mark) @optional;
+	fn usz mark() @optional;
+	fn void*! acquire(usz size, bool clear, usz alignment, usz offset);
+	fn void*! resize(void* ptr, usz new_size, usz alignment, usz offset);
+	fn void release(void* ptr, bool aligned);
 }

+struct AlignedBlock
+{
+	usz len;
+	void* start;
+}
+
+/**
+ * @require bytes > 0
+ * @require alignment > 0
+ **/
+macro void*! @aligned_alloc(#alloc_fn, usz bytes, usz alignment, usz offset)
+{
+	usz header = mem::aligned_offset(AlignedBlock.sizeof + offset, alignment) - offset;
+	$if @typekind(#alloc_fn(bytes)) == OPTIONAL:
+		void* data = #alloc_fn(header + bytes)!;
+	$else
+		void* data = #alloc_fn(header + bytes);
+	$endif
+	void* mem = mem::aligned_pointer(data + header + offset, alignment) - offset;
+	assert(mem > data);
+	AlignedBlock* desc = (AlignedBlock*)mem - 1;
+	*desc = { bytes, data };
+	return mem;
+}
+
+/**
+ * @require bytes > 0
+ * @require alignment > 0
+ **/
+macro void*! @aligned_calloc(#calloc_fn, usz bytes, usz alignment, usz offset)
+{
+	usz header = mem::aligned_offset(AlignedBlock.sizeof + offset, alignment) - offset;
+	$if @typekind(#calloc_fn(bytes)) == OPTIONAL:
+		void* data = #calloc_fn(header + bytes)!;
+	$else
+		void* data = #calloc_fn(header + bytes);
+	$endif
+	void* mem = mem::aligned_pointer(data + header + offset, alignment) - offset;
+	AlignedBlock* desc = (AlignedBlock*)mem - 1;
+	assert(mem > data);
+	*desc = { bytes, data };
+	return mem;
+}
+
+/**
+ * @require bytes > 0
+ * @require alignment > 0
+ **/
+macro void*! @aligned_realloc(#calloc_fn, #free_fn, void* old_pointer, usz bytes, usz alignment, usz offset)
+{
+	AlignedBlock* desc = (AlignedBlock*)old_pointer - 1;
+	void* data_start = desc.start;
+	void* new_data = @aligned_calloc(#calloc_fn, bytes, alignment, offset)!;
+	mem::copy(new_data, old_pointer, desc.len < bytes ? desc.len : bytes, mem::DEFAULT_MEM_ALIGNMENT, mem::DEFAULT_MEM_ALIGNMENT);
+	$if @typekind(#free_fn(data_start)) == OPTIONAL:
+	#free_fn(data_start)!;
+	$else
+	#free_fn(data_start);
+	$endif
+	return new_data;
+}
+
+macro void! @aligned_free(#free_fn, void* old_pointer)
+{
+	AlignedBlock* desc = (AlignedBlock*)old_pointer - 1;
+	$if @typekind(#free_fn(desc.start)) == OPTIONAL:
+	#free_fn(desc.start)!;
+	$else
+	#free_fn(desc.start);
+	$endif
+}
+
+def MemoryAllocFn = fn char[]!(usz);
+
 fault AllocationFailure
 {
-    OUT_OF_MEMORY,
-    UNSUPPORTED_OPERATION,
-    CHUNK_TOO_LARGE,
-}
-
-
-
-fn void*! Allocator.alloc(Allocator* allocator, usz size) @inline
-{
-	return allocator.function(allocator, size, 0, 0, null, ALLOC);
-}
-
-/**
- * @require alignment && math::is_power_of_2(alignment)
- */
-fn void*! Allocator.alloc_aligned(Allocator* allocator, usz size, usz alignment, usz offset = 0) @inline
-{
-	return allocator.function(allocator, size, alignment, offset, null, ALIGNED_ALLOC);
-}
-
-fn void*! Allocator.realloc(Allocator* allocator, void* old_pointer, usz size) @inline
-{
-	return allocator.function(allocator, size, 0, 0, old_pointer, REALLOC);
-}
-
-/**
- * @require alignment && math::is_power_of_2(alignment)
- */
-fn void*! Allocator.realloc_aligned(Allocator* allocator, void* old_pointer, usz size, usz alignment, usz offset = 0) @inline
-{
-	return allocator.function(allocator, size, alignment, offset, old_pointer, ALIGNED_REALLOC);
-}
-
-fn usz! Allocator.mark(Allocator* allocator) @inline
-{
-	return (usz)(uptr)allocator.function(allocator, 0, 0, 0, null, MARK);
-}
-
-
-fn void*! Allocator.calloc(Allocator* allocator, usz size) @inline
-{
-	return allocator.function(allocator, size, 0, 0, null, CALLOC);
-}
-
-/**
- * @require alignment && math::is_power_of_2(alignment)
- */
-fn void*! Allocator.calloc_aligned(Allocator* allocator, usz size, usz alignment, usz offset = 0) @inline
-{
-	return allocator.function(allocator, size, alignment, offset, null, ALIGNED_CALLOC);
-}
-
-fn void! Allocator.free(Allocator* allocator, void* old_pointer) @inline
-{
-	allocator.function(allocator, 0, 0, 0, old_pointer, FREE)?;
-}
-
-fn void! Allocator.free_aligned(Allocator* allocator, void* old_pointer) @inline
-{
-	allocator.function(allocator, 0, 0, 0, old_pointer, ALIGNED_FREE)?;
-}
-
-fn void Allocator.reset(Allocator* allocator, usz mark = 0)
-{
-	allocator.function(allocator, mark, 0, 0, null, RESET)!!;
+	OUT_OF_MEMORY,
+	CHUNK_TOO_LARGE,
 }

 fn usz alignment_for_allocation(usz alignment) @inline @private
 {
-	if (alignment < mem::DEFAULT_MEM_ALIGNMENT)
-	{
-		alignment = mem::DEFAULT_MEM_ALIGNMENT;
-	}
-	return alignment;
+	return alignment < mem::DEFAULT_MEM_ALIGNMENT ? alignment = mem::DEFAULT_MEM_ALIGNMENT : alignment;
+}
+
+// Allocator "functions"
+
+macro void*! Allocator.alloc_checked(&self, usz size)
+{
+	$if env::TESTING:
+		char* data = self.acquire(size, false, 0, 0)!;
+		mem::set(data, 0xAA, size, mem::DEFAULT_MEM_ALIGNMENT);
+		return data;
+	$else
+		return self.acquire(size, false, 0, 0);
+	$endif
+}
+
+macro void*! Allocator.calloc_checked(&self, usz size)
+{
+	return self.acquire(size, true, 0, 0);
+}
+macro void*! Allocator.realloc_checked(&self, void* ptr, usz new_size)
+{
+	return self.resize(ptr, new_size, 0, 0);
+}
+
+macro Allocator.new_array(&self, $Type, usz size, usz end_padding = 0)
+{
+	return (($Type*)self.alloc_checked($Type.sizeof * size + end_padding))[:size]!!;
+}
+
+macro Allocator.new_array_checked(&self, $Type, usz size, usz end_padding = 0)
+{
+	return (($Type*)self.alloc_checked($Type.sizeof * size + end_padding))[:size];
+}
+
+macro Allocator.new_zero_array(&self, $Type, usz size, usz end_padding = 0)
+{
+	return (($Type*)self.calloc_checked($Type.sizeof * size + end_padding))[:size]!!;
+}
+
+macro Allocator.new_zero_array_checked(&self, $Type, usz size, usz end_padding = 0)
+{
+	return (($Type*)self.calloc_checked($Type.sizeof * size + end_padding))[:size];
+}
+
+macro Allocator.new(&self, $Type, usz end_padding = 0) @nodiscard
+{
+	return ($Type*)self.alloc_checked($Type.sizeof + end_padding)!!;
+}
+
+macro Allocator.new_checked(&self, $Type, usz end_padding = 0) @nodiscard
+{
+	return ($Type*)self.alloc_checked($Type.sizeof + end_padding);
+}
+
+macro Allocator.new_clear(&self, $Type, usz end_padding = 0) @nodiscard
+{
+	return ($Type*)self.calloc_checked($Type.sizeof + end_padding)!!;
+}
+
+macro Allocator.new_clear_checked(&self, $Type, usz end_padding = 0) @nodiscard
+{
+	return ($Type*)self.calloc_checked($Type.sizeof + end_padding);
+}
+
+macro Allocator.clone(&self, value)
+{
+	var x = self.alloc($typeof(value));
+	*x = value;
+	return x;
+}
+
+macro void* Allocator.alloc(&self, usz size) @nodiscard
+{
+	return self.alloc_checked(size)!!;
+}
+macro void* Allocator.calloc(&self, usz size) @nodiscard
+{
+	return self.acquire(size, true, 0, 0)!!;
+}
+macro void* Allocator.realloc(&self, void* ptr, usz new_size) @nodiscard
+{
+	return self.resize(ptr, new_size, 0, 0)!!;
+}
+
+macro void*! Allocator.alloc_aligned(&self, usz size, usz alignment, usz offset = 0)
+{
+	$if env::TESTING:
+		char* data = self.acquire(size, false, alignment, offset)!;
+		mem::set(data, 0xAA, size, mem::DEFAULT_MEM_ALIGNMENT);
+		return data;
+	$else
+		return self.acquire(size, false, alignment, offset);
+	$endif
+}
+macro void*! Allocator.calloc_aligned(&self, usz size, usz alignment, usz offset = 0)
+{
+	return self.acquire(size, true, alignment, offset);
+}
+macro void*! Allocator.realloc_aligned(&self, void* ptr, usz new_size, usz alignment = 0, usz offset = 0)
+{
+	return self.resize(ptr, new_size, alignment, offset);
+}
+
+macro void Allocator.free(&self, void* ptr)
+{
+	$if env::TESTING:
+		if (ptr) ((char*)ptr)[0] = 0xBA;
+	$endif
+	self.release(ptr, false);
+}
+macro void Allocator.free_aligned(&self, void* ptr)
+{
+	$if env::TESTING:
+		if (ptr) ((char*)ptr)[0] = 0xBA;
+	$endif
+	self.release(ptr, true);
 }


-
--- a/lib/std/core/mem_array.c3
+++ b/lib/std/core/mem_array.c3
@@ -1,31 +0,0 @@
-// Copyright (c) 2021-2023 Christoffer Lerno. All rights reserved.
-// Use of this source code is governed by the MIT license
-// a copy of which can be found in the LICENSE_STDLIB file.
-
-module std::core::mem::array;
-
-/**
- * @require usz.max / elements > $Type.sizeof
- **/
-macro alloc($Type, usz elements) @deprecated => malloc($Type, elements);
-
-/**
- * @require usz.max / elements > $Type.sizeof
- **/
-macro talloc($Type, usz elements) @deprecated => tmalloc($Type, elements);
-
-/**
- * @require (usz.max / elements > $Type.sizeof)
- **/
-macro make($Type, usz elements, Allocator* using = mem::heap()) @deprecated
-{
-	return calloc($Type, elements, .using = using);
-}
-
-/**
- * @require (usz.max / elements > $Type.sizeof)
- **/
-macro tmake($Type, usz elements) @deprecated
-{
-	return tcalloc($Type, elements);
-}
--- a/lib/std/core/os/wasm_memory.c3
+++ b/lib/std/core/os/wasm_memory.c3
@@ -11,22 +11,22 @@ struct WasmMemory
 	uptr use;
 }

-fn char[]! WasmMemory.allocate_block(WasmMemory* this, usz bytes)
+fn char[]! WasmMemory.allocate_block(&self, usz bytes)
 {
-	if (!this.allocation)
+	if (!self.allocation)
 	{
-		this.allocation = $$wasm_memory_size(0) * WASM_BLOCK_SIZE;
+		self.allocation = $$wasm_memory_size(0) * WASM_BLOCK_SIZE;
 	}
-	isz bytes_required = bytes + this.use - this.allocation;
-    if (bytes_required <= 0)
+	isz bytes_required = bytes + self.use - self.allocation;
+	if (bytes_required <= 0)
 	{
-		defer this.use += bytes;
-		return ((char*)this.use)[:bytes];
+		defer self.use += bytes;
+		return ((char*)self.use)[:bytes];
 	}

 	usz blocks_required = (bytes_required + WASM_BLOCK_SIZE + 1) / WASM_BLOCK_SIZE;
-	if ($$wasm_memory_grow(0, blocks_required) == -1) return AllocationFailure.OUT_OF_MEMORY!;
-	this.allocation = $$wasm_memory_size(0) * WASM_BLOCK_SIZE;
-	defer this.use += bytes;
-	return ((char*)this.use)[:bytes];
+	if ($$wasm_memory_grow(0, blocks_required) == -1) return AllocationFailure.OUT_OF_MEMORY?;
+	self.allocation = $$wasm_memory_size(0) * WASM_BLOCK_SIZE;
+	defer self.use += bytes;
+	return ((char*)self.use)[:bytes];
 }
--- a/lib/std/core/private/main_stub.c3
+++ b/lib/std/core/private/main_stub.c3
@@ -7,7 +7,11 @@ macro usz _strlen(ptr) @private
 	return len;
 }

-macro int @main_to_err_main(#m, int, char**) => catch? #m() ? 1 : 0;
+macro int @main_to_err_main(#m, int, char**)
+{
+	if (catch #m()) return 1;
+	return 0;
+}
 macro int @main_to_int_main(#m, int, char**) => #m();
 macro int @main_to_void_main(#m, int, char**)
 {
@@ -17,7 +21,7 @@ macro int @main_to_void_main(#m, int, char**)

 macro String[] args_to_strings(int argc, char** argv) @private
 {
-	String[] list = malloc(String, argc);
+	String[] list = mem::new_array(String, argc);
 	for (int i = 0; i < argc; i++)
 	{
 		char* arg = argv[i];
@@ -32,7 +36,8 @@ macro int @main_to_err_main_args(#m, int argc, char** argv)
 {
 	String[] list = args_to_strings(argc, argv);
 	defer free(list.ptr);
-	return catch? #m(list) ? 1 : 0;
+	if (catch #m(list)) return 1;
+	return 0;
 }

 macro int @main_to_int_main_args(#m, int argc, char** argv)
@@ -50,7 +55,7 @@ macro int @main_to_void_main_args(#m, int argc, char** argv)
 	return 0;
 }

-$if (env::OS_TYPE == OsType.WIN32)
+module std::core::main_stub @if(env::WIN32);

 extern fn Char16** _win_command_line_to_argv_w(ushort* cmd_line, int* argc_ptr) @extern("CommandLineToArgvW");

@@ -63,12 +68,12 @@ macro String[] win_command_line_to_strings(ushort* cmd_line) @private

 macro String[] wargs_strings(int argc, Char16** argv) @private
 {
-	String[] list = malloc(String, argc);
+	String[] list = mem::new_array(String, argc);
 	for (int i = 0; i < argc; i++)
 	{
 		Char16* arg = argv[i];
 		Char16[] argstring = arg[:_strlen(arg)];
-		list[i] = string::from_utf16(argstring) ?? "?".copy();
+		list[i] = string::new_from_utf16(argstring) ?? "?".copy();
 	}
 	return list[:argc];
 }
@@ -79,7 +84,11 @@ macro void release_wargs(String[] list) @private
 	free(list.ptr);
 }

-macro int @win_to_err_main_noargs(#m, void* handle, Char16* cmd_line, int show_cmd) => catch? #m() ? 1 : 0;
+macro int @win_to_err_main_noargs(#m, void* handle, Char16* cmd_line, int show_cmd)
+{
+	if (catch #m()) return 1;
+	return 0;
+}
 macro int @win_to_int_main_noargs(#m, void* handle, Char16* cmd_line, int show_cmd) => #m();
 macro int @win_to_void_main_noargs(#m, void* handle, Char16* cmd_line, int show_cmd)
 {
@@ -91,14 +100,15 @@ macro int @win_to_err_main_args(#m, void* handle, Char16* cmd_line, int show_cmd
 {
 	String[] args = win_command_line_to_strings(cmd_line);
 	defer release_wargs(args);
-    return catch? #m(args) ? 1 : 0;
+	if (catch #m(args)) return 1;
+	return 0;
 }

 macro int @win_to_int_main_args(#m, void* handle, Char16* cmd_line, int show_cmd)
 {
 	String[] args = win_command_line_to_strings(cmd_line);
 	defer release_wargs(args);
-    return #m(args);
+	return #m(args);
 }

 macro int @win_to_void_main_args(#m, void* handle, Char16* cmd_line, int show_cmd)
@@ -113,14 +123,15 @@ macro int @win_to_err_main(#m, void* handle, Char16* cmd_line, int show_cmd)
 {
 	String[] args = win_command_line_to_strings(cmd_line);
 	defer release_wargs(args);
-    return catch? #m(handle, args, show_cmd) ? 1 : 0;
+	if (catch #m(handle, args, show_cmd)) return 1;
+	return 0;
 }

 macro int @win_to_int_main(#m, void* handle, Char16* cmd_line, int show_cmd)
 {
 	String[] args = win_command_line_to_strings(cmd_line);
 	defer release_wargs(args);
-    return #m(handle, args, show_cmd);
+	return #m(handle, args, show_cmd);
 }

 macro int @win_to_void_main(#m, void* handle, Char16* cmd_line, int show_cmd)
@@ -135,14 +146,15 @@ macro int @wmain_to_err_main_args(#m, int argc, Char16** argv)
 {
 	String[] args = wargs_strings(argc, argv);
 	defer release_wargs(args);
-    return catch? #m(args) ? 1 : 0;
+	if (catch #m(args)) return 1;
+	return 1;
 }

 macro int @wmain_to_int_main_args(#m, int argc, Char16** argv)
 {
 	String[] args = wargs_strings(argc, argv);
 	defer release_wargs(args);
-    return #m(args);
+	return #m(args);
 }

 macro int @wmain_to_void_main_args(#m, int argc, Char16** argv)
@@ -152,5 +164,3 @@ macro int @wmain_to_void_main_args(#m, int argc, Char16** argv)
 	#m(args);
 	return 0;
 }
-
-$endif
--- a/lib/std/core/runtime.c3
+++ b/lib/std/core/runtime.c3
@@ -2,108 +2,249 @@
 // Use of this source code is governed by the MIT license
 // a copy of which can be found in the LICENSE_STDLIB file.
 module std::core::runtime;
+import libc;

-struct VirtualAny
+struct AnyStruct
 {
-    void* ptr;
-    typeid type_id;
+	void* ptr;
+	typeid type;
 }

-struct VirtualContainer
+struct SubArrayStruct
 {
-    void* ptr;
-    void* impl_ptr;
+	void* ptr;
+	usz len;
 }

-struct SubArrayContainer
+def BenchmarkFn = fn void!();
+
+struct BenchmarkUnit
 {
-    void* ptr;
-    usz len;
+	String name;
+	BenchmarkFn func;
 }

-struct VarArrayHeader
+fn BenchmarkUnit[] benchmark_collection_create(Allocator* allocator = mem::heap())
 {
-    usz size;
-    usz capacity;
-    void *allocator;
+	BenchmarkFn[] fns = $$BENCHMARK_FNS;
+	String[] names = $$BENCHMARK_NAMES;
+	BenchmarkUnit[] benchmarks = allocator.new_array(BenchmarkUnit, names.len);
+	foreach (i, benchmark : fns)
+	{
+		benchmarks[i] = { names[i], fns[i] };
+	}
+	return benchmarks;
 }

-typedef TestFn = fn void!();
+const DEFAULT_BENCHMARK_WARMUP_ITERATIONS = 3;
+const DEFAULT_BENCHMARK_MAX_ITERATIONS = 10000;

-struct TestRunner
+uint benchmark_warmup_iterations @private = DEFAULT_BENCHMARK_WARMUP_ITERATIONS;
+uint benchmark_max_iterations @private = DEFAULT_BENCHMARK_MAX_ITERATIONS;
+
+fn void set_benchmark_warmup_iterations(uint value) @builtin
 {
-	String[] test_names;
-	TestFn[] test_fns;
-	JmpBuf buf;
+    benchmark_warmup_iterations = value;
 }

-fn TestRunner test_runner_create()
+fn void set_benchmark_max_iterations(uint value) @builtin
 {
-	return TestRunner {
-		.test_fns = $$TEST_FNS,
-		.test_names = $$TEST_NAMES,
+    assert(value > 0);
+    benchmark_max_iterations = value;
+}
+
+fn bool run_benchmarks(BenchmarkUnit[] benchmarks)
+{
+	int benchmarks_passed = 0;
+	int benchmark_count = benchmarks.len;
+	usz max_name;
+
+	foreach (&unit : benchmarks)
+	{
+		if (max_name < unit.name.len) max_name = unit.name.len;
+	}
+
+	usz len = max_name + 9;
+
+	DString name = dstring::temp_with_capacity(64);
+	name.append_repeat('-', len / 2);
+	name.append(" BENCHMARKS ");
+	name.append_repeat('-', len - len / 2);
+
+	io::printn(name);
+
+	name.clear();
+
+	long sys_clock_started;
+	long sys_clock_finished;
+	long sys_clocks;
+	Clock clock;
+	anyfault err;
+
+	foreach(unit : benchmarks)
+	{
+		defer name.clear();
+		name.appendf("Benchmarking %s ", unit.name);
+		name.append_repeat('.', max_name - unit.name.len + 2);
+		io::printf("%s ", name.str_view());
+
+		for (uint i = 0; i < benchmark_warmup_iterations; i++)
+		{
+			err = @catch(unit.func()) @inline;
+			@volatile_load(err);
+		}
+
+		clock = std::time::clock::now();
+		sys_clock_started = $$sysclock();
+
+		for (uint i = 0; i < benchmark_max_iterations; i++)
+		{
+			err = @catch(unit.func()) @inline;
+			@volatile_load(err);
+		}
+
+		sys_clock_finished = $$sysclock();
+		NanoDuration nano_seconds = clock.mark();
+		sys_clocks = sys_clock_finished - sys_clock_started;
+
+		if (err)
+		{
+			io::printfn("[failed] Failed due to: %s", err);
+			continue;
+		}
+
+		io::printfn("[ok] %.2f ns, %.2f CPU's clocks", (float)nano_seconds / benchmark_max_iterations, (float)sys_clocks / benchmark_max_iterations);
+		benchmarks_passed++;
+	}
+
+	io::printfn("\n%d benchmark%s run.\n", benchmark_count, benchmark_count > 1 ? "s" : "");
+	io::printfn("Benchmarks Result: %s. %d passed, %d failed.",
+		benchmarks_passed < benchmark_count ? "FAILED" : "ok",
+		benchmarks_passed,
+		benchmark_count - benchmarks_passed);
+
+	return benchmark_count == benchmarks_passed;
+}
+
+fn bool default_benchmark_runner()
+{
+	@pool()
+	{
+		return run_benchmarks(benchmark_collection_create(mem::temp()));
 	};
 }

-import libc;
+def TestFn = fn void!();
+
+struct TestUnit
+{
+	String name;
+	TestFn func;
+}
+
+fn TestUnit[] test_collection_create(Allocator* allocator = mem::heap())
+{
+	TestFn[] fns = $$TEST_FNS;
+	String[] names = $$TEST_NAMES;
+	TestUnit[] tests = allocator.new_array(TestUnit, names.len);
+	foreach (i, test : fns)
+	{
+		tests[i] = { names[i], fns[i] };
+	}
+	return tests;
+}
+
+struct TestContext
+{
+	JmpBuf buf;
+}
+
+// Sort the tests by their name in ascending order.
+fn int cmp_test_unit(TestUnit a, TestUnit b)
+{
+	usz an = a.name.len;
+	usz bn = b.name.len;
+	if (an > bn) @swap(a, b);
+	foreach (i, ac : a.name)
+	{
+		char bc = b.name[i];
+		if (ac != bc) return an > bn ? bc - ac : ac - bc;
+	}
+	return (int)(an - bn);
+}
+
+TestContext* test_context @private;

-TestRunner* current_runner @private;
 fn void test_panic(String message, String file, String function, uint line)
 {
 	io::printn("[error]");
-	io::printfn("\n Error: %s", message);
+	io::print("\n Error: ");
+	io::print(message);
+	io::printn();
 	io::printfn("  - in %s %s:%s.\n", function, file, line);
-	libc::longjmp(&current_runner.buf, 1);
+	libc::longjmp(&test_context.buf, 1);
 }

-fn bool TestRunner.run(TestRunner* runner)
+fn bool run_tests(TestUnit[] tests)
 {
-	current_runner = runner;
+	usz max_name;
+	foreach (&unit : tests)
+	{
+		if (max_name < unit.name.len) max_name = unit.name.len;
+	}
+	quicksort(tests, &cmp_test_unit);
+
+	TestContext context;
+	test_context = &context;
+
 	PanicFn old_panic = builtin::panic;
 	defer builtin::panic = old_panic;
 	builtin::panic = &test_panic;
 	int tests_passed = 0;
-	int tests = runner.test_names.len;
-	io::printn("----- TESTS -----");
-	foreach(i, String name : runner.test_names)
+	int test_count = tests.len;
+	DString name = dstring::temp_with_capacity(64);
+	usz len = max_name + 9;
+	name.append_repeat('-', len / 2);
+	name.append(" TESTS ");
+	name.append_repeat('-', len - len / 2);
+	io::printn(name);
+	name.clear();
+	foreach(unit : tests)
 	{
-		io::printf("Testing %s ... ", name);
-		if (libc::setjmp(&runner.buf) == 0)
+		defer name.clear();
+		name.appendf("Testing %s ", unit.name);
+		name.append_repeat('.', max_name - unit.name.len + 2);
+		io::printf("%s ", name.str_view());
+		if (libc::setjmp(&context.buf) == 0)
 		{
-			if (catch err = runner.test_fns[i]())
+			if (catch err = unit.func())
 			{
-				io::printn("[failed]");
+				io::printfn("[failed] Failed due to: %s", err);
 				continue;
 			}
 			io::printn("[ok]");
 			tests_passed++;
 		}
 	}
-	io::printfn("\n%d test(s) run.\n", tests);
-	io::print("Test Result: ");
-	if (tests_passed < tests)
-	{
-		io::print("FAILED");
-	}
-	else
-	{
-		io::print("ok");
-	}
-	io::printfn(". %d passed, %d failed.", tests_passed, tests - tests_passed);
-	return tests == tests_passed;
+	io::printfn("\n%d test%s run.\n", test_count, test_count > 1 ? "s" : "");
+	io::printfn("Test Result: %s. %d passed, %d failed.",
+		tests_passed < test_count ? "FAILED" : "ok", tests_passed, test_count - tests_passed);
+	return test_count == tests_passed;
 }

-fn bool __run_default_test_runner()
+fn bool default_test_runner()
 {
-	return test_runner_create().run();
+	@pool()
+	{
+		return run_tests(test_collection_create(mem::temp()));
+	};
 }

-$if (!env::COMPILER_LIBC_AVAILABLE && env::ARCH_TYPE == ArchType.WASM32 || env::ARCH_TYPE == ArchType.WASM64)
+module std::core::runtime @if(WASM_NOLIBC);

 extern fn void __wasm_call_ctors();
 fn void wasm_initialize() @extern("_initialize") @wasm
 {
 	// The linker synthesizes this to call constructors.
 	__wasm_call_ctors();
-}
-$endif
+}
--- a/lib/std/core/str.c3
+++ b/lib/std/core/str.c3
@@ -1,259 +0,0 @@
-module std::core::str;
-
-fn VarString join(String[] s, String joiner)
-{
-	if (!s.len) return (VarString)null;
-	usz total_size = joiner.len * s.len;
-	foreach (String* &str : s)
-	{
-		total_size += str.len;
-	}
-	VarString res = string::new_with_capacity(total_size);
-	res.append(s[0]);
-	foreach (String* &str : s[1..])
-	{
-		res.append(joiner);
-		res.append(*str);
-	}
-	return res;
-}
-
-macro bool char_in_set(char c, String set)
-{
-	foreach (ch : set)
-	{
-		if (ch == c) return true;
-	}
-	return false;
-}
-
-macro char_is_space_tab(char c) @private
-{
-	return c == ' ' || c == '\t';
-}
-
-macro to_integer($Type, String string) @private
-{
-	usz len = string.len;
-	usz index = 0;
-	char* ptr = string.ptr;
-	while (index < len && char_is_space_tab(ptr[index])) index++;
-	if (len == index) return NumberConversion.EMPTY_STRING!;
-	bool is_negative;
-	switch (string[index])
-	{
-		case '-':
-			if ($Type.min == 0) return NumberConversion.NEGATIVE_VALUE!;
-			is_negative = true;
-			index++;
-		case '+':
-			index++;
-		default:
-			break;
-	}
-	if (len == index) return NumberConversion.MALFORMED_INTEGER!;
-	$Type base = 10;
-	if (string[index] == '0')
-	{
-		index++;
-		if (index == len) return ($Type)0;
-		switch (string[index])
-		{
-			case 'x':
-			case 'X':
-				base = 16;
-				index++;
-			case 'b':
-			case 'B':
-				base = 2;
-				index++;
-			case 'o':
-			case 'O':
-				base = 8;
-				index++;
-			default:
-				break;
-		}
-		if (len == index) return NumberConversion.MALFORMED_INTEGER!;
-	}
-	$Type value = 0;
-	while (index != len)
-	{
-		char c = {|
-			char ch = string[index++];
-			if (base != 16 || ch < 'A') return (char)(ch - '0');
-			if (ch <= 'F') return (char)(ch - 'A');
-			if (ch < 'a') return NumberConversion.MALFORMED_INTEGER!;
-			if (ch > 'f') return NumberConversion.MALFORMED_INTEGER!;
-			return (char)(ch - 'a');
-		|}?;
-		if (c >= base) return NumberConversion.MALFORMED_INTEGER!;
-		value = {|
-			if (is_negative)
-			{
-				$Type new_value = value * base - c;
-				if (new_value > value) return NumberConversion.INTEGER_OVERFLOW!;
-				return new_value;
-			}
-			$Type new_value = value * base + c;
-			if (new_value < value) return NumberConversion.INTEGER_OVERFLOW!;
-			return new_value;
-		|}?;
-	}
-	return value;
-}
-
-fn float! to_float(String string) => floatparse(string, float);
-fn double! to_double(String string) => floatparse(string, double);
-fn int128! to_int128(String string) => to_integer(int128, string);
-fn long! to_long(String string) => to_integer(long, string);
-fn int! to_int(String string) => to_integer(int, string);
-fn short! to_short(String string) => to_integer(short, string);
-fn ichar! to_ichar(String string) => to_integer(ichar, string);
-
-fn uint128! to_uint128(String str) => to_integer(uint128, str);
-fn ulong! to_ulong(String str) => to_integer(ulong, str);
-fn uint! to_uint(String str) => to_integer(uint, str);
-fn ushort! to_ushort(String str) => to_integer(ushort, str);
-fn char! to_uchar(String str) => to_integer(char, str);
-
-fn String trim(String string, String to_trim = "\t\n\r ") @deprecated => string.trim(to_trim);
-
-fn bool starts_with(String s, String needle) @deprecated => s.starts_with(needle);
-
-fn String[] tsplit(String s, String needle) @deprecated => s.split(needle, .using = mem::temp()) @inline;
-fn String[] split(String s, String needle, Allocator* using = mem::heap()) @deprecated => s.split(needle, .using = using);
-fn usz! rindex_of(String s, String needle) @deprecated => s.rindex_of(needle);
-fn usz! index_of(String s, String needle) @deprecated => s.index_of(needle);
-
-fn ZString String.zstrcopy(String s, Allocator* using = mem::heap()) @deprecated => s.zstr_copy(using);
-fn ZString String.zstrtcopy(String s) @deprecated => s.zstr_tcopy();
-
-fn ZString copy_zstring(String s, Allocator* using = mem::heap()) @deprecated => s.zstr_copy(using);
-fn String copyz(String s, Allocator* using = mem::heap()) @deprecated => s.copy(using);
-fn ZString tcopy_zstring(String s) @deprecated => s.zstr_tcopy();
-
-fn bool compare(String a, String b)
-{
-	if (a.len != b.len) return false;
-	foreach (i, c : a)
-	{
-		if (c != b[i]) return false;
-	}
-	return true;
-}
-
-fault UnicodeResult
-{
-	INVALID_UTF8,
-	INVALID_UTF16,
-	CONVERSION_FAILED,
-}
-
-fn usz utf8_codepoints(String utf8)
-{
-	usz len = 0;
-	foreach (char c : utf8)
-	{
-		if (c & 0xC0 != 0x80) len++;
-	}
-	return len;
-}
-
-fn Char32[]! utf8to32(String utf8, Allocator* using = mem::heap())
-{
-	usz codepoints = conv::utf8_codepoints(utf8);
-	Char32* data = malloc_checked(Char32, codepoints + 1, .using = using)?;
-	conv::utf8to32_unsafe(utf8, data)?;
-	data[codepoints] = 0;
-	return data[:codepoints];
-}
-
-fn String utf32to8(Char32[] utf32, Allocator* using = mem::heap())
-{
-	usz len = conv::utf8len_for_utf32(utf32);
-	char* data = malloc_checked(len + 1, .using = using)!!;
-	conv::utf32to8_unsafe(utf32, data);
-	data[len] = 0;
-	return (String)data[:len];
-}
-
-fn Char16[]! utf8to16(String utf8, Allocator* using = mem::heap())
-{
-	usz len16 = conv::utf16len_for_utf8(utf8);
-	Char16* data = malloc_checked(Char16, len16 + 1, .using = using)?;
-	conv::utf8to16_unsafe(utf8, data)?;
-	data[len16] = 0;
-	return data[:len16];
-}
-
-
-fn String! utf16to8(Char16[] utf16, Allocator* using = mem::heap())
-{
-	usz len = conv::utf8len_for_utf16(utf16);
-	char* data = malloc_checked(len + 1, .using = using)?;
-	conv::utf16to8_unsafe(utf16, data)?;
-	data[len] = 0;
-	return (String)data[:len];
-}
-
-fn String copy(String s, Allocator* using = mem::heap()) @deprecated
-{
-    usz len = s.len;
-    ZString str_copy = s.zstr_copy(using) @inline;
-    return (String)str_copy[:len];
-}
-
-fn String tcopy(String s) @deprecated
-{
-    usz len = s.len;
-    ZString str_copy = s.zstr_tcopy() @inline;
-    return (String)str_copy[:len];
-}
-
-fn String tconcat(String s1, String s2)
-{
-    usz full_len = s1.len + s2.len;
-    char* str = tmalloc(full_len + 1);
-    usz s1_len = s1.len;
-    mem::copy(str, s1.ptr, s1_len);
-    mem::copy(str + s1_len, s2.ptr, s2.len);
-    str[full_len] = 0;
-    return (String)str[:full_len];
-}
-
-fn String concat(String s1, String s2)
-{
-    usz full_len = s1.len + s2.len;
-    char* str = malloc(full_len + 1);
-    usz s1_len = s1.len;
-    mem::copy(str, s1.ptr, s1_len);
-    mem::copy(str + s1_len, s2.ptr, s2.len);
-    str[full_len] = 0;
-    return (String)str[:full_len];
-}
-
-fn String ZString.as_str(ZString str)
-{
-	return (String)((char*)str)[:str.len()];
-}
-
-fn usz ZString.char_len(ZString str)
-{
-	usz len = 0;
-	char* ptr = (char*)str;
-	while (char c = ptr++[0])
-	{
-		if (c & 0xC0 != 0x80) len++;
-	}
-	return len;
-}
-
-fn usz ZString.len(ZString str)
-{
-	usz len = 0;
-    char* ptr = (char*)str;
-    while (char c = ptr++[0]) len++;
-    return len;
-}
-
--- a/lib/std/core/string.c3
+++ b/lib/std/core/string.c3
@@ -1,8 +1,17 @@
 module std::core::string;
+import std::ascii;

-typedef ZString = distinct inline char*;
-typedef Char32 = uint;
-typedef Char16 = ushort;
+distinct ZString = inline char*;
+distinct WString = inline Char16*;
+def Char32 = uint;
+def Char16 = ushort;
+
+fault UnicodeResult
+{
+	INVALID_UTF8,
+	INVALID_UTF16,
+	CONVERSION_FAILED,
+}

 const uint SURROGATE_OFFSET @private = 0x10000;
 const uint SURROGATE_GENERIC_MASK @private = 0xF800;
@@ -22,24 +31,23 @@ fault NumberConversion
 	FLOAT_OUT_OF_RANGE,
 }

-macro String printf(String fmt, ..., Allocator* using = mem::heap())
+macro String tformat(String fmt, ...)
 {
-	@stack_mem(256; Allocator* mem)
+	DString str = dstring::temp_with_capacity(fmt.len + $vacount * 8);
+	str.appendf(fmt, $vasplat());
+	return str.str_view();
+}
+
+macro String new_format(String fmt, ..., Allocator* allocator = mem::heap())
+{
+	@pool(allocator)
 	{
-		DString str;
-		str.init(.using = mem);
-		str.printf(fmt, $vasplat());
-		return str.copy_str(using);
+		DString str = dstring::temp_with_capacity(fmt.len + $vacount * 8);
+		str.appendf(fmt, $vasplat());
+		return str.copy_str(allocator);
 	};
 }

-macro String tprintf(String fmt, ...)
-{
-	DString str;
-	str.tinit();
-	str.printf(fmt, $vasplat());
-	return str.str();
-}

 macro bool char_in_set(char c, String set)
 {
@@ -47,11 +55,36 @@ macro bool char_in_set(char c, String set)
 	return false;
 }

+fn String join_new(String[] s, String joiner, Allocator* allocator = mem::heap())
+{
+	if (!s)
+	{
+		return (String)allocator.new_zero_array(char, 2)[:0];
+	}
+
+	usz total_size = joiner.len * s.len;
+	foreach (String* &str : s)
+	{
+		total_size += str.len;
+	}
+	@pool(allocator)
+	{
+		DString res = dstring::temp_with_capacity(total_size);
+		res.append(s[0]);
+		foreach (String* &str : s[1..])
+		{
+			res.append(joiner);
+			res.append(*str);
+		}
+		return res.copy_str(allocator);
+	};
+}
+
 /**
 * @param [in] string
 * @param [in] to_trim
 **/
-fn String String.trim(String string, String to_trim = "\t\n\r ")
+fn String String.trim(string, String to_trim = "\t\n\r ")
 {
 	usz start = 0;
 	usz len = string.len;
@@ -66,7 +99,7 @@ fn String String.trim(String string, String to_trim = "\t\n\r ")
 * @param [in] string
 * @param [in] needle
 **/
-fn bool String.starts_with(String string, String needle)
+fn bool String.starts_with(string, String needle)
 {
 	if (needle.len > string.len) return false;
 	if (!needle.len) return true;
@@ -77,7 +110,7 @@ fn bool String.starts_with(String string, String needle)
 * @param [in] string
 * @param [in] needle
 **/
-fn bool String.ends_with(String string, String needle)
+fn bool String.ends_with(string, String needle)
 {
 	if (needle.len > string.len) return false;
 	if (!needle.len) return true;
@@ -90,7 +123,7 @@ fn bool String.ends_with(String string, String needle)
 * @param [in] string
 * @param [in] needle
 **/
-fn String String.strip(String string, String needle)
+fn String String.strip(string, String needle)
 {
 	if (!needle.len || !string.starts_with(needle)) return string;
 	return string[needle.len..];
@@ -102,7 +135,7 @@ fn String String.strip(String string, String needle)
 * @param [in] string
 * @param [in] needle
 **/
-fn String String.strip_end(String string, String needle)
+fn String String.strip_end(string, String needle)
 {
 	if (!needle.len || !string.ends_with(needle)) return string;
 	// Note that this is the safe way if we want to support zero length.
@@ -115,20 +148,20 @@ fn String String.strip_end(String string, String needle)
 *
 * @param [in] s
 * @param [in] needle
- * @param [&inout] using "The allocator, defaults to the heap allocator"
+ * @param [&inout] allocator "The allocator, defaults to the heap allocator"
 * @param max "Max number of elements, 0 means no limit, defaults to 0"
 * @require needle.len > 0 "The needle must be at least 1 character long"
 * @ensure return.len > 0
 **/
-fn String[] String.split(String s, String needle, usz max = 0, Allocator* using = mem::heap())
+fn String[] String.split(s, String needle, usz max = 0, Allocator* allocator = mem::heap())
 {
 	usz capacity = 16;
 	usz i = 0;
-	String* holder = malloc(String, capacity, .using = using);
+	String* holder = allocator.new_array(String, capacity);
 	bool no_more = false;
 	while (!no_more)
 	{
-		usz! index = i == max - 1 ? SearchResult.MISSING! : s.index_of(needle);
+		usz! index = i == max - 1 ? SearchResult.MISSING? : s.index_of(needle);
 		String res @noinit;
 		if (try index)
 		{
@@ -143,7 +176,7 @@ fn String[] String.split(String s, String needle, usz max = 0, Allocator* using
 		if (i == capacity)
 		{
 			capacity *= 2;
-			holder = realloc(holder, String.sizeof * capacity, .using = using);
+			holder = allocator.realloc(holder, String.sizeof * capacity);
 		}
 		holder[i++] = res;
 	}
@@ -158,11 +191,52 @@ fn String[] String.split(String s, String needle, usz max = 0, Allocator* using
 * @param [in] needle
 * @param max "Max number of elements, 0 means no limit, defaults to 0"
 **/
-fn String[] String.tsplit(String s, String needle, usz max = 0)
+fn String[] String.tsplit(s, String needle, usz max = 0)
 {
 	return s.split(needle, max, mem::temp()) @inline;
 }

+fn bool String.contains(s, String needle)
+{
+	return @ok(s.index_of(needle));
+}
+
+/**
+ * Find the index of the first incidence of a string.
+ *
+ * @param [in] s
+ * @pure
+ * @ensure return < s.len
+ * @return "the index of the needle"
+ * @return! SearchResult.MISSING "if the needle cannot be found"
+ **/
+fn usz! String.index_of_char(s, char needle)
+{
+	foreach (i, c : s)
+	{
+		if (c == needle) return i;
+	}
+	return SearchResult.MISSING?;
+}
+
+/**
+ * Find the index of the first incidence of a string.
+ *
+ * @param [in] s
+ * @pure
+ * @ensure return < s.len
+ * @return "the index of the needle"
+ * @return! SearchResult.MISSING "if the needle cannot be found"
+ **/
+fn usz! String.rindex_of_char(s, char needle)
+{
+	foreach_r (i, c : s)
+	{
+		if (c == needle) return i;
+	}
+	return SearchResult.MISSING?;
+}
+
 /**
 * Find the index of the first incidence of a string.
 *
@@ -170,31 +244,22 @@ fn String[] String.tsplit(String s, String needle, usz max = 0)
 * @param [in] needle
 * @pure
 * @ensure return < s.len
- * @require needle.len > 0 "The needle must be len 1 or more"
+ * @require needle.len > 0 : "The needle must be len 1 or more"
+ * @return "the index of the needle"
+ * @return! SearchResult.MISSING "if the needle cannot be found"
 **/
-fn usz! String.index_of(String s, String needle)
+fn usz! String.index_of(s, String needle)
 {
-	usz match = 0;
 	usz needed = needle.len;
-	usz index_start = 0;
-	char search = needle[0];
-	foreach (usz i, char c : s)
+	if (needed > 0 && s.len >= needed)
 	{
-		if (c == search)
+		char first = needle[0];
+		foreach (i, c: s[..^needed])
 		{
-			if (!match) index_start = i;
-			match++;
-			if (match == needed) return index_start;
-			search = needle[match];
-			continue;
-		}
-		if (match)
-		{
-			match = 0;
-			search = needle[0];
+			if (c == first && s[i:needed] == needle) return i;
 		}
 	}
-	return SearchResult.MISSING!;
+	return SearchResult.MISSING?;
 }

 /**
@@ -205,88 +270,348 @@ fn usz! String.index_of(String s, String needle)
 * @pure
 * @ensure return < s.len
 * @require needle.len > 0 "The needle must be len 1 or more"
+ * @return "the index of the needle"
+ * @return! SearchResult.MISSING "if the needle cannot be found"
 **/
-fn usz! String.rindex_of(String s, String needle)
+fn usz! String.rindex_of(s, String needle)
 {
-	usz match = 0;
 	usz needed = needle.len;
-	usz index_start = 0;
-	char search = needle[^1];
-	foreach_r (usz i, char c : s)
+	if (needed > 0 && s.len >= needed)
 	{
-		if (c == search)
+		char first = needle[0];
+		foreach_r (i, c: s[..^needed])
 		{
-			if (!match) index_start = i;
-			match++;
-			if (match == needed) return index_start - needle.len + 1;
-			search = needle[^(match + 1)];
-			continue;
-		}
-		if (match)
-		{
-			match = 0;
-			search = needle[^1];
+			if (c == first && s[i:needed] == needle) return i;
 		}
 	}
-	return SearchResult.MISSING!;
+	return SearchResult.MISSING?;
 }

-fn ZString String.zstr_copy(String s, Allocator* using = mem::heap())
+fn String ZString.str_view(str)
 {
-    usz len = s.len;
-    char* str = malloc(len + 1, .using = using);
-    mem::copy(str, s.ptr, len);
-    str[len] = 0;
-    return (ZString)str;
+	return (String)(str[:str.len()]);
 }

-fn String String.concat(String s1, String s2, Allocator* using = mem::heap())
+fn usz ZString.char_len(str)
 {
-    usz full_len = s1.len + s2.len;
-    char* str = malloc(full_len + 1, .using = using);
-    usz s1_len = s1.len;
-    mem::copy(str, s1.ptr, s1_len);
-    mem::copy(str + s1_len, s2.ptr, s2.len);
-    str[full_len] = 0;
-    return (String)str[:full_len];
+	usz len = 0;
+	char* ptr = (char*)str;
+	while (char c = ptr++[0])
+	{
+		if (c & 0xC0 != 0x80) len++;
+	}
+	return len;
 }

-fn String String.tconcat(String s1, String s2) => s1.concat(s2, mem::temp());
-
-
-fn ZString String.zstr_tcopy(String s) => s.zstr_copy(mem::temp()) @inline;
-
-fn String String.copy(String s, Allocator* using = mem::heap())
+fn usz ZString.len(str)
 {
-    usz len = s.len;
-    char* str = malloc(len + 1, .using = using);
-    mem::copy(str, s.ptr, len);
-    str[len] = 0;
-    return (String)str[:len];
+	usz len = 0;
+	char* ptr = (char*)str;
+	while (char c = ptr++[0]) len++;
+	return len;
 }

-fn String String.tcopy(String s) => s.copy(mem::temp()) @inline;

-fn String ZString.copy(ZString z, Allocator* using = mem::heap()) => z.as_str().copy(using) @inline;
-fn String ZString.tcopy(ZString z) => z.as_str().copy(mem::temp()) @inline;
+fn ZString String.zstr_copy(s, Allocator* allocator = mem::heap())
+{
+	usz len = s.len;
+	char* str = allocator.alloc(len + 1);
+	mem::copy(str, s.ptr, len);
+	str[len] = 0;
+	return (ZString)str;
+}

-fn Char16[]! String.to_utf16(String s, Allocator* using = mem::heap())
+fn String String.concat(s1, String s2, Allocator* allocator = mem::heap())
+{
+	usz full_len = s1.len + s2.len;
+	char* str = allocator.alloc(full_len + 1);
+	usz s1_len = s1.len;
+	mem::copy(str, s1.ptr, s1_len);
+	mem::copy(str + s1_len, s2.ptr, s2.len);
+	str[full_len] = 0;
+	return (String)str[:full_len];
+}
+
+fn String String.tconcat(s1, String s2) => s1.concat(s2, mem::temp());
+
+
+fn ZString String.zstr_tcopy(s) => s.zstr_copy(mem::temp()) @inline;
+
+fn String String.copy(s, Allocator* allocator = mem::heap())
+{
+	usz len = s.len;
+	char* str = allocator.alloc(len + 1);
+	mem::copy(str, s.ptr, len);
+	str[len] = 0;
+	return (String)str[:len];
+}
+
+fn void String.free(&s, Allocator* allocator = mem::heap())
+{
+	if (!s.len) return;
+	allocator.free(s.ptr);
+	*s = "";
+}
+
+fn String String.tcopy(s) => s.copy(mem::temp()) @inline;
+
+fn String ZString.copy(z, Allocator* allocator = mem::temp())
+{
+	return z.str_view().copy(allocator) @inline;
+}
+
+fn String ZString.tcopy(z)
+{
+	return z.str_view().copy(mem::temp()) @inline;
+}
+
+/**
+ * Convert an UTF-8 string to UTF-16
+ * @return "The UTF-16 string as a slice, allocated using the given allocator"
+ * @return! UnicodeResult.INVALID_UTF8 "If the string contained an invalid UTF-8 sequence"
+ * @return! AllocationFailure "If allocation of the string fails"
+ **/
+fn Char16[]! String.to_new_utf16(s, Allocator* allocator = mem::heap())
 {
 	usz len16 = conv::utf16len_for_utf8(s);
-	Char16* data = malloc_checked(Char16, len16 + 1, .using = using)?;
-	conv::utf8to16_unsafe(s, data)?;
+	Char16* data = allocator.new_array_checked(Char16, len16 + 1)!;
+	conv::utf8to16_unsafe(s, data)!;
 	data[len16] = 0;
 	return data[:len16];
 }

-fn String! from_utf16(Char16[] utf16, Allocator* using = mem::heap())
+/**
+ * Convert an UTF-8 string to UTF-16
+ * @return "The UTF-16 string as a slice, allocated using the given allocator"
+ * @return! UnicodeResult.INVALID_UTF8 "If the string contained an invalid UTF-8 sequence"
+ * @return! AllocationFailure "If allocation of the string fails"
+ **/
+fn Char16[]! String.to_temp_utf16(s)
 {
-	usz len = conv::utf8len_for_utf16(utf16);
-	char* data = malloc_checked(len + 1, .using = using)?;
-	conv::utf16to8_unsafe(utf16, data)?;
+	return s.to_new_utf16(mem::temp());
+}
+
+fn WString! String.to_new_wstring(s, Allocator* allocator = mem::heap())
+{
+	return (WString)s.to_new_utf16(allocator).ptr;
+}
+
+fn WString! String.to_temp_wstring(s)
+{
+	return (WString)s.to_temp_utf16().ptr;
+}
+
+fn Char32[]! String.to_new_utf32(s, Allocator* allocator = mem::heap())
+{
+	usz codepoints = conv::utf8_codepoints(s);
+	Char32* data = allocator.new_array(Char32, codepoints + 1);
+	conv::utf8to32_unsafe(s, data)!;
+	data[codepoints] = 0;
+	return data[:codepoints];
+}
+
+fn Char32[]! String.to_temp_utf32(s)
+{
+	return s.to_new_utf32(mem::temp());
+}
+
+fn void String.convert_ascii_to_lower(s)
+{
+	foreach (&c : s) if (c.is_upper()) *c += 'a' - 'A';
+}
+
+fn String String.new_ascii_to_lower(s, Allocator* allocator = mem::heap())
+{
+	String copy = s.copy(allocator);
+	copy.convert_ascii_to_lower();
+	return copy;
+}
+
+fn String String.temp_ascii_to_lower(s, Allocator* allocator = mem::heap())
+{
+	return s.new_ascii_to_lower(mem::temp());
+}
+
+fn void String.convert_ascii_to_upper(s)
+{
+	foreach (&c : s) if (c.is_lower()) *c -= 'a' - 'A';
+}
+
+fn String String.new_ascii_to_upper(s, Allocator* allocator = mem::heap())
+{
+	String copy = s.copy(allocator);
+	copy.convert_ascii_to_upper();
+	return copy;
+}
+
+fn StringIterator String.iterator(s)
+{
+	return { s, 0 };
+}
+
+fn String String.temp_ascii_to_upper(s)
+{
+	return s.new_ascii_to_upper(mem::temp());
+}
+
+fn String! new_from_utf32(Char32[] utf32, Allocator* allocator = mem::heap())
+{
+	usz len = conv::utf8len_for_utf32(utf32);
+	char* data = allocator.alloc_checked(len + 1)!;
+	defer catch allocator.free(data);
+	conv::utf32to8_unsafe(utf32, data);
 	data[len] = 0;
 	return (String)data[:len];
 }

+fn String! new_from_utf16(Char16[] utf16, Allocator* allocator = mem::heap())
+{
+	usz len = conv::utf8len_for_utf16(utf16);
+	char* data = allocator.alloc_checked(len + 1)!;
+	defer catch allocator.free(data);
+	conv::utf16to8_unsafe(utf16, data)!;
+	data[len] = 0;
+	return (String)data[:len];
+}
+
+fn String! new_from_wstring(WString wstring, Allocator* allocator = mem::heap())
+{
+	usz utf16_len;
+	while (wstring[utf16_len] != 0) utf16_len++;
+	Char16[] utf16 = wstring[:utf16_len];
+	return new_from_utf16(utf16, allocator);
+}
+
+fn String! temp_from_wstring(WString wstring) => new_from_wstring(wstring, mem::temp()) @inline;
+fn String! temp_from_utf16(Char16[] utf16) => new_from_utf16(utf16, mem::temp()) @inline;
+
+fn usz String.utf8_codepoints(s)
+{
+	usz len = 0;
+	foreach (char c : s)
+	{
+		if (c & 0xC0 != 0x80) len++;
+	}
+	return len;
+}
+
+macro String.to_integer(string, $Type)
+{
+	usz len = string.len;
+	usz index = 0;
+	char* ptr = string.ptr;
+	while (index < len && ascii::is_blank_m(ptr[index])) index++;
+	if (len == index) return NumberConversion.EMPTY_STRING?;
+	bool is_negative;
+	switch (string[index])
+	{
+		case '-':
+			if ($Type.min == 0) return NumberConversion.NEGATIVE_VALUE?;
+			is_negative = true;
+			index++;
+		case '+':
+			index++;
+		default:
+			break;
+	}
+	if (len == index) return NumberConversion.MALFORMED_INTEGER?;
+	$Type base = 10;
+	if (string[index] == '0')
+	{
+		index++;
+		if (index == len) return ($Type)0;
+		switch (string[index])
+		{
+			case 'x':
+			case 'X':
+				base = 16;
+				index++;
+			case 'b':
+			case 'B':
+				base = 2;
+				index++;
+			case 'o':
+			case 'O':
+				base = 8;
+				index++;
+			default:
+				break;
+		}
+		if (len == index) return NumberConversion.MALFORMED_INTEGER?;
+	}
+	$Type value = 0;
+	while (index != len)
+	{
+		char c = {|
+			char ch = string[index++];
+			if (base != 16 || ch < 'A') return (char)(ch - '0');
+			if (ch <= 'F') return (char)(ch - 'A');
+			if (ch < 'a') return NumberConversion.MALFORMED_INTEGER?;
+			if (ch > 'f') return NumberConversion.MALFORMED_INTEGER?;
+			return (char)(ch - 'a');
+		|}!;
+		if (c >= base) return NumberConversion.MALFORMED_INTEGER?;
+		value = {|
+			if (is_negative)
+			{
+				$Type new_value = value * base - c;
+				if (new_value > value) return NumberConversion.INTEGER_OVERFLOW?;
+				return new_value;
+			}
+			$Type new_value = value * base + c;
+			if (new_value < value) return NumberConversion.INTEGER_OVERFLOW?;
+			return new_value;
+		|}!;
+	}
+	return value;
+}
+
+fn int128! String.to_int128(s) => s.to_integer(int128);
+fn long! String.to_long(s) => s.to_integer(long);
+fn int! String.to_int(s) => s.to_integer(int);
+fn short! String.to_short(s) => s.to_integer(short);
+fn ichar! String.to_ichar(s) => s.to_integer(ichar);
+
+fn uint128! String.to_uint128(s) => s.to_integer(uint128);
+fn ulong! String.to_ulong(s) => s.to_integer(ulong);
+fn uint! String.to_uint(s) => s.to_integer(uint);
+fn ushort! String.to_ushort(s) => s.to_integer(ushort);
+fn char! String.to_uchar(s) => s.to_integer(char);
+
+fn double! String.to_double(s) => s.to_real(double);
+fn float! String.to_float(s) => s.to_real(float);
+
+fn Splitter String.splitter(self, String split)
+{
+	return Splitter { self, split, 0 };
+}
+
+struct Splitter
+{
+	String string;
+	String split;
+	usz current;
+}
+
+fn void Splitter.reset(&self)
+{
+	self.current = 0;
+}
+
+fn String! Splitter.next(&self)
+{
+	usz len = self.string.len;
+	usz current = self.current;
+	if (current >= len) return IteratorResult.NO_MORE_ELEMENT?;
+	String remaining = self.string[current..];
+	usz! next = remaining.index_of(self.split);
+	if (try next)
+	{
+		defer self.current = current + next + self.split.len;
+		return remaining[:next];
+	}
+	self.current = len;
+	return remaining;
+}
+

-fn Char16[]! String.to_temp_utf16(String s) => s.to_utf16(mem::temp());
--- a/lib/std/core/string_iterator.c3
+++ b/lib/std/core/string_iterator.c3
@@ -6,18 +6,18 @@ struct StringIterator
 	usz current;
 }

-fn void StringIterator.reset(StringIterator* this)
+fn void StringIterator.reset(&self)
 {
-	this.current = 0;
+	self.current = 0;
 }

-fn Char32! StringIterator.next(StringIterator* this)
+fn Char32! StringIterator.next(&self)
 {
-	usz len = this.utf8.len;
-	usz current = this.current;
-	if (current >= len) return IteratorResult.NO_MORE_ELEMENT!;
+	usz len = self.utf8.len;
+	usz current = self.current;
+	if (current >= len) return IteratorResult.NO_MORE_ELEMENT?;
 	usz read = (len - current < 4 ? len - current : 4);
-	Char32 res = conv::utf8_to_char32(&this.utf8[current], &read)?;
-	this.current += read;
+	Char32 res = conv::utf8_to_char32(&self.utf8[current], &read)!;
+	self.current += read;
 	return res;
-}
+}
--- a/lib/std/core/string_to_real.c3
+++ b/lib/std/core/string_to_real.c3
@@ -1,4 +1,4 @@
-module std::core::str;
+module std::core::string;
 import std::math;

 // Float parsing based on code in Musl floatscan.c by Rich Felker.
@@ -64,7 +64,7 @@ macro double! decfloat(char[] chars, int $bits, int $emin, int sign)
 		got_rad = true;
 		if (index == last_char)
 		{
-			if (!got_digit) return NumberConversion.MALFORMED_FLOAT!;
+			if (!got_digit) return NumberConversion.MALFORMED_FLOAT?;
 			return sign * 0.0;
 		}
 		if (index != last_char && (c = chars[++index]) == '0')
@@ -83,7 +83,7 @@ macro double! decfloat(char[] chars, int $bits, int $emin, int sign)
 		switch
 		{
 			case c == '.':
-				if (got_rad) return NumberConversion.MALFORMED_FLOAT!;
+				if (got_rad) return NumberConversion.MALFORMED_FLOAT?;
 				got_rad = true;
 				lrp = dc;
 			case k < KMAX - 3:
@@ -105,7 +105,7 @@ macro double! decfloat(char[] chars, int $bits, int $emin, int sign)
 				got_digit = true;
 			default:
 				dc++;
-        		if (c != '0') x[KMAX - 4] |= 1;
+				if (c != '0') x[KMAX - 4] |= 1;

 		}
 		if (index == last_char) break;
@@ -113,24 +113,24 @@ macro double! decfloat(char[] chars, int $bits, int $emin, int sign)
 		c = chars[++index];
 	}
 	if (!got_rad) lrp = dc;
-	if (!got_digit) return NumberConversion.MALFORMED_FLOAT!;
+	if (!got_digit) return NumberConversion.MALFORMED_FLOAT?;
 	if ((c | 32) == 'e')
 	{
-		if (last_char == index) return NumberConversion.MALFORMED_FLOAT!;
-		long e10 = str::to_long((String)chars[index + 1..]) ?? NumberConversion.MALFORMED_FLOAT!?;
+		if (last_char == index) return NumberConversion.MALFORMED_FLOAT?;
+		long e10 = String.to_long((String)chars[index + 1..]) ?? NumberConversion.MALFORMED_FLOAT?!;
 		lrp += e10;
 	}
 	else if (index != last_char)
 	{
-		return NumberConversion.MALFORMED_FLOAT!;
+		return NumberConversion.MALFORMED_FLOAT?;
 	}
 	// Handle zero specially to avoid nasty special cases later
 	if (!x[0]) return sign * 0.0;

 	// Optimize small integers (w/no exponent) and over/under-flow
 	if (lrp == dc && dc < 10 && ($bits > 30 || (ulong)x[0] >> $bits == 0)) return sign * (double)x[0];
-	if (lrp > - $emin / 2) return NumberConversion.FLOAT_OUT_OF_RANGE!;
-	if (lrp < $emin - 2 * math::DOUBLE_MANT_DIG) return NumberConversion.FLOAT_OUT_OF_RANGE!;
+	if (lrp > - $emin / 2) return NumberConversion.FLOAT_OUT_OF_RANGE?;
+	if (lrp < $emin - 2 * math::DOUBLE_MANT_DIG) return NumberConversion.FLOAT_OUT_OF_RANGE?;

 	// Align incomplete final B1B digit
 	if (j)
@@ -235,7 +235,7 @@ macro double! decfloat(char[] chars, int $bits, int $emin, int sign)
 			carry = (1000000000 >> sh) * tmp;
 			if (k == a && !x[k])
 			{
-			 	a = (a + 1) & MASK;
+				a = (a + 1) & MASK;
 				i--;
 				rp -= 9;
 			}
@@ -320,7 +320,7 @@ macro double! decfloat(char[] chars, int $bits, int $emin, int sign)
 			y *= 0.5;
 			e2++;
 		}
-		if (e2 + math::DOUBLE_MANT_DIG > emax || (denormal && frac)) return NumberConversion.MALFORMED_FLOAT!;
+		if (e2 + math::DOUBLE_MANT_DIG > emax || (denormal && frac)) return NumberConversion.MALFORMED_FLOAT?;
 	}
 	return math::scalbn(y, e2);
 }
@@ -351,7 +351,7 @@ macro double! hexfloat(char[] chars, int $bits, int $emin, int sign)
 		got_rad = true;
 		if (index == last_char)
 		{
-			if (!got_digit) return NumberConversion.MALFORMED_FLOAT!;
+			if (!got_digit) return NumberConversion.MALFORMED_FLOAT?;
 			return sign * 0.0;
 		}
 		if (index != last_char && (c = chars[++index]) == '0')
@@ -369,7 +369,7 @@ macro double! hexfloat(char[] chars, int $bits, int $emin, int sign)
 	{
 		if (c == '.')
 		{
-			if (got_rad) return NumberConversion.MALFORMED_FLOAT!;
+			if (got_rad) return NumberConversion.MALFORMED_FLOAT?;
 			got_rad = true;
 			rp = dc;
 		}
@@ -396,20 +396,20 @@ macro double! hexfloat(char[] chars, int $bits, int $emin, int sign)
 		if (index == last_char) break;
 		c = chars[++index];
 	}
-	if (!got_digit) return NumberConversion.MALFORMED_FLOAT!;
+	if (!got_digit) return NumberConversion.MALFORMED_FLOAT?;
 	if (!got_rad) rp = dc;
 	for (; dc < 8; dc++) x *= 16;

 	long e2;
 	if ((c | 32) == 'p')
 	{
-		long e2val = str::to_long((String)chars[index + 1..]) ?? NumberConversion.MALFORMED_FLOAT!?;
-    	e2 = e2val;
+		long e2val = String.to_long((String)chars[index + 1..]) ?? (NumberConversion.MALFORMED_FLOAT?)!;
+		e2 = e2val;
 	}
 	e2 += 4 * rp - 32;
 	if (!x) return sign * 0.0;
-	if (e2 > -$emin) return NumberConversion.FLOAT_OUT_OF_RANGE!;
-	if (e2 < $emin - 2 * math::DOUBLE_MANT_DIG) return NumberConversion.FLOAT_OUT_OF_RANGE!;
+	if (e2 > -$emin) return NumberConversion.FLOAT_OUT_OF_RANGE?;
+	if (e2 < $emin - 2 * math::DOUBLE_MANT_DIG) return NumberConversion.FLOAT_OUT_OF_RANGE?;

 	while (x < 0x80000000)
 	{
@@ -444,12 +444,12 @@ macro double! hexfloat(char[] chars, int $bits, int $emin, int sign)
 	}
 	y = bias + sign * (double)x + sign * y;
 	y -= bias;
-	if (!y) return NumberConversion.FLOAT_OUT_OF_RANGE!;
+	if (!y) return NumberConversion.FLOAT_OUT_OF_RANGE?;

 	return math::scalbn(y, (int)e2);
 }

-macro floatparse(String chars, $Type) @private
+macro String.to_real(chars, $Type) @private
 {
 	int sign = 1;
 	$switch ($Type)
@@ -460,23 +460,23 @@ macro floatparse(String chars, $Type) @private
 		const int BITS = math::DOUBLE_MANT_DIG;
 		const int EMIN = math::DOUBLE_MIN_EXP - BITS;
 	$case float128:
-		$assert(false, "Not yet supported");
+		$error "Not yet supported";
 	$default:
-		$assert(false, "Unexpected type");
+		$error "Unexpected type";
 	$endswitch

- 	while (chars.len && chars[0] == ' ') chars = chars[1..];
- 	if (!chars.len) return NumberConversion.MALFORMED_FLOAT!;
- 	switch (chars[0])
- 	{
- 	    case '-':
- 	        sign = -1;
- 	        nextcase;
- 	    case '+':
- 	        chars = chars[1..];
- 	}
- 	if (chars == "infinity" || chars == "INFINITY") return sign * $Type.inf;
- 	if (chars == "NAN" || chars == "nan") return $Type.nan;
+	while (chars.len && chars[0] == ' ') chars = chars[1..];
+	if (!chars.len) return NumberConversion.MALFORMED_FLOAT?;
+	switch (chars[0])
+	{
+		case '-':
+			sign = -1;
+			nextcase;
+		case '+':
+			chars = chars[1..];
+	}
+	if (chars == "infinity" || chars == "INFINITY") return sign * $Type.inf;
+	if (chars == "NAN" || chars == "nan") return $Type.nan;

 	if (chars.len > 2 && chars[0] == '0' && (chars[1] | 32) == 'x')
 	{
--- a/lib/std/core/types.c3
+++ b/lib/std/core/types.c3
@@ -1,3 +1,4 @@
+
 module std::core::types;
 import libc;

@@ -10,107 +11,103 @@ fault ConversionResult
 /**
 * @require $Type.kindof.is_int() || $Type.kindof == TypeKind.ENUM "Argument was not an integer"
 **/
-macro variant_to_int(variant v, $Type)
+macro any_to_int(any* v, $Type)
 {
-	typeid variant_type = v.type;
-	TypeKind kind = variant_type.kindof;
+	typeid any_type = v.type;
+	TypeKind kind = any_type.kindof;
 	if (kind == TypeKind.ENUM)
 	{
-		variant_type = variant_type.inner;
-		kind = variant_type.kindof;
+		any_type = any_type.inner;
+		kind = any_type.kindof;
 	}
-	bool is_mixed_signed = $Type.kindof != variant_type.kindof;
+	bool is_mixed_signed = $Type.kindof != any_type.kindof;
 	$Type max = $Type.max;
 	$Type min = $Type.min;
-	switch (variant_type)
+	switch (any_type)
 	{
 		case ichar:
 			ichar c = *(char*)v.ptr;
-			if (is_mixed_signed && c < 0) return ConversionResult.VALUE_OUT_OF_UNSIGNED_RANGE!;
+			if (is_mixed_signed && c < 0) return ConversionResult.VALUE_OUT_OF_UNSIGNED_RANGE?;
 			return ($Type)c;
 		case short:
 			short s = *(short*)v.ptr;
-			if (is_mixed_signed && s < 0) return ConversionResult.VALUE_OUT_OF_UNSIGNED_RANGE!;
-			if (s > max || s < min) return ConversionResult.VALUE_OUT_OF_RANGE!;
+			if (is_mixed_signed && s < 0) return ConversionResult.VALUE_OUT_OF_UNSIGNED_RANGE?;
+			if (s > max || s < min) return ConversionResult.VALUE_OUT_OF_RANGE?;
 			return ($Type)s;
 		case int:
 			int i = *(int*)v.ptr;
-			if (is_mixed_signed && i < 0) return ConversionResult.VALUE_OUT_OF_UNSIGNED_RANGE!;
-			if (i > max || i < min) return ConversionResult.VALUE_OUT_OF_RANGE!;
+			if (is_mixed_signed && i < 0) return ConversionResult.VALUE_OUT_OF_UNSIGNED_RANGE?;
+			if (i > max || i < min) return ConversionResult.VALUE_OUT_OF_RANGE?;
 			return ($Type)i;
 		case long:
 			long l = *(long*)v.ptr;
-			if (is_mixed_signed && l < 0) return ConversionResult.VALUE_OUT_OF_UNSIGNED_RANGE!;
-			if (l > max || l < min) return ConversionResult.VALUE_OUT_OF_RANGE!;
+			if (is_mixed_signed && l < 0) return ConversionResult.VALUE_OUT_OF_UNSIGNED_RANGE?;
+			if (l > max || l < min) return ConversionResult.VALUE_OUT_OF_RANGE?;
 			return ($Type)l;
 		case int128:
 			int128 i = *(int128*)v.ptr;
-			if (is_mixed_signed && i < 0) return ConversionResult.VALUE_OUT_OF_UNSIGNED_RANGE!;
-			if (i > max || i < min) return ConversionResult.VALUE_OUT_OF_RANGE!;
+			if (is_mixed_signed && i < 0) return ConversionResult.VALUE_OUT_OF_UNSIGNED_RANGE?;
+			if (i > max || i < min) return ConversionResult.VALUE_OUT_OF_RANGE?;
 			return ($Type)i;
 		case char:
 			char c = *(char*)v.ptr;
-			if (c > max) return ConversionResult.VALUE_OUT_OF_RANGE!;
+			if (c > max) return ConversionResult.VALUE_OUT_OF_RANGE?;
 			return ($Type)c;
 		case ushort:
 			ushort s = *(ushort*)v.ptr;
-			if (s > max || s < min) return ConversionResult.VALUE_OUT_OF_RANGE!;
+			if (s > max || s < min) return ConversionResult.VALUE_OUT_OF_RANGE?;
 			return ($Type)s;
 		case uint:
 			uint i = *(uint*)v.ptr;
-			if (i > max || i < min) return ConversionResult.VALUE_OUT_OF_RANGE!;
+			if (i > max || i < min) return ConversionResult.VALUE_OUT_OF_RANGE?;
 			return ($Type)i;
 		case ulong:
 			ulong l = *(ulong*)v.ptr;
-			if (l > max || l < min) return ConversionResult.VALUE_OUT_OF_RANGE!;
+			if (l > max || l < min) return ConversionResult.VALUE_OUT_OF_RANGE?;
 			return ($Type)l;
 		case uint128:
 			uint128 i = *(uint128*)v.ptr;
-			if (i > max || i < min) return ConversionResult.VALUE_OUT_OF_RANGE!;
+			if (i > max || i < min) return ConversionResult.VALUE_OUT_OF_RANGE?;
 			return ($Type)i;
 		default:
 			unreachable();
 	}
 }

+fn bool typeid.is_subtype_of(self, typeid other)
+{
+	while (self != void.typeid)
+	{
+		if (self == other) return true;
+		self = self.parentof;
+	}
+	return false;
+}
+
+macro bool is_subtype_of($Type, $OtherType)
+{
+	var $typeid = $Type.typeid;
+	$switch ($Type)
+		$case $OtherType: return true;
+		$default: return false;
+	$endswitch
+}
 macro bool is_numerical($Type)
 {
 	var $kind = $Type.kindof;
-	$if ($kind == TypeKind.DISTINCT)
-		return is_numerical($Type.inner);
+	$if $kind == TypeKind.DISTINCT:
+		return is_numerical($typefrom($Type.inner));
 	$else
 		return $kind == TypeKind.SIGNED_INT || $kind == TypeKind.UNSIGNED_INT || $kind == TypeKind.FLOAT
 			|| $kind == TypeKind.VECTOR;
 	$endif
 }

-fn bool TypeKind.is_int(TypeKind kind) @inline
+fn bool TypeKind.is_int(kind) @inline
 {
 	return kind == TypeKind.SIGNED_INT || kind == TypeKind.UNSIGNED_INT;
 }

-macro bool is_indexable($Type)
-{
-	return $checks($Type t, int i, t[i]);
-}
-
-macro bool is_comparable($Type)
-{
-	var $kind = $Type.kindof;
-	$if ($kind == TypeKind.DISTINCT)
-		return is_comparable($Type.inner);
-	$else
-		return $kind == TypeKind.SIGNED_INT || $kind == TypeKind.UNSIGNED_INT || $kind == TypeKind.FLOAT
-			|| $kind == TypeKind.VECTOR || $kind == TypeKind.BOOL || $kind == TypeKind.POINTER
-			|| $kind == TypeKind.ENUM;
-	$endif
-}
-
-macro bool is_equatable($Type)
-{
-	return $checks($Type a, a == a);
-}
-
 macro bool is_subarray_convertable($Type)
 {
 	$switch ($Type.kindof)
@@ -139,6 +136,18 @@ macro bool is_intlike($Type)
 	$endswitch
 }

+macro bool is_underlying_int($Type)
+{
+	$switch ($Type.kindof)
+		$case SIGNED_INT:
+		$case UNSIGNED_INT:
+			return true;
+		$case DISTINCT:
+			return is_underlying_int($typefrom($Type.inner));
+		$default:
+			return false;
+	$endswitch
+}

 macro bool is_float($Type) => $Type.kindof == TypeKind.FLOAT;

@@ -161,18 +170,13 @@ macro bool is_vector($Type)

 macro TypeKind inner_kind($Type)
 {
-	$if ($Type.kindof == TypeKind.DISTINCT)
+	$if $Type.kindof == TypeKind.DISTINCT:
 		return inner_kind($typefrom($Type.inner));
 	$else
 		return $Type.kindof;
 	$endif
 }

-macro bool @convertable(#a, $TypeB) @builtin
-{
-	return $checks($TypeB x = #a);
-}
-
 macro bool is_same($TypeA, $TypeB)
 {
 	return $TypeA.typeid == $TypeB.typeid;
@@ -180,12 +184,12 @@ macro bool is_same($TypeA, $TypeB)

 macro bool @has_same(#a, #b, ...)
 {
-	var $type_a = $typeof(#a).typeid;
-	$if ($type_a != $typeof(#b).typeid)
-	    return false;
+	var $type_a = @typeid(#a);
+	$if $type_a != @typeid(#b):
+		return false;
 	$endif
 	$for (var $i = 0; $i < $vacount; $i++)
-		$if ($typeof($vaexpr($i)).typeid != $type_a)
+		$if @typeid($vaexpr($i)) != $type_a:
 			return false;
 		$endif
 	$endfor
@@ -207,58 +211,97 @@ macro bool may_load_atomic($Type)
 	$endswitch
 }

+macro lower_to_atomic_compatible_type($Type) 
+{
+	$switch ($Type.kindof)
+    $case SIGNED_INT:
+	  $case UNSIGNED_INT:
+      return $Type.typeid;
+		$case DISTINCT:
+			return lower_to_atomic_compatible_type($Type.inner);
+		$case FLOAT:
+			$switch ($Type)
+				$case float16: 
+					return ushort.typeid;
+				$case float: 
+					return uint.typeid;
+				$case double:
+					return ulong.typeid;
+				$case float128:
+					return uint128.typeid;
+				$default: 
+					return void.typeid;
+			$endswitch
+		$default:
+			return void.typeid;
+  $endswitch
+}
+
 macro bool is_promotable_to_floatlike($Type) => types::is_floatlike($Type) || types::is_int($Type);
 macro bool is_promotable_to_float($Type) => types::is_float($Type) || types::is_int($Type);

 macro bool is_same_vector_type($Type1, $Type2)
 {
-	$if ($Type1.kindof != TypeKind.VECTOR)
+	$if $Type1.kindof != TypeKind.VECTOR:
 		return $Type2.kindof != TypeKind.VECTOR;
 	$else
 		return $Type1.inner == $Type2.inner && $Type1.len == $Type2.len;
 	$endif
 }

-macro bool is_equatable_value(value)
+macro bool is_equatable_type($Type)
 {
-	$if ($defined(value.less) || $defined(value.compare_to) || $defined(value.equals))
+	$if $defined($Type.less) || $defined($Type.compare_to) || $defined($Type.equals):
 		return true;
 	$else
-		return is_equatable($typeof(value));
+		return $Type.is_eq;
 	$endif
 }

+/**
+ * Checks if a type implements the copy protocol.
+ **/
+macro bool implements_copy($Type)
+{
+	return $defined($Type.copy) && $defined($Type.free);
+}
+
+macro bool is_equatable_value(value)
+{
+	return is_equatable_type($typeof(value));
+}
+
 macro bool is_comparable_value(value)
 {
-	$if ($defined(value.less) || $defined(value.compare_to))
+	$if $defined(value.less) || $defined(value.compare_to):
 		return true;
 	$else
-		return is_comparable($typeof(value));
+		return $typeof(value).is_ordered;
 	$endif
 }

 enum TypeKind : char
 {
-    VOID,
-    BOOL,
-    SIGNED_INT,
-    UNSIGNED_INT,
-    FLOAT,
-    TYPEID,
-    ANYERR,
-    VARIANT,
-    ENUM,
-    FAULT,
-    STRUCT,
-    UNION,
-    BITSTRUCT,
-    FUNC,
-    OPTIONAL,
-    ARRAY,
-    SUBARRAY,
-    VECTOR,
-    DISTINCT,
-    POINTER,
+	VOID,
+	BOOL,
+	SIGNED_INT,
+	UNSIGNED_INT,
+	FLOAT,
+	TYPEID,
+	ANYFAULT,
+	ANY,
+	ENUM,
+	FAULT,
+	STRUCT,
+	UNION,
+	BITSTRUCT,
+	FUNC,
+	OPTIONAL,
+	ARRAY,
+	SUBARRAY,
+	VECTOR,
+	DISTINCT,
+	POINTER,
 }

 struct TypeEnum
--- a/lib/std/core/values.c3
+++ b/lib/std/core/values.c3
@@ -1,18 +1,25 @@
 module std::core::values;

+macro typeid @typeid(#value) @builtin => $typeof(#value).typeid;
 macro TypeKind @typekind(#value) @builtin => $typeof(#value).kindof;
 macro bool @typeis(#value, $Type) @builtin => $typeof(#value).typeid == $Type.typeid;
+/**
+ * Return true if two values have the same type before any conversions.
+ **/
+macro bool @is_same_type(#value1, #value2) => $typeof(#value1).typeid == $typeof(#value2).typeid;
 macro bool @is_bool(#value) => types::is_bool($typeof(#value));
 macro bool @is_int(#value) => types::is_int($typeof(#value));
-macro bool @convertable_to(#a, #b) => $checks($typeof(#b) x = #a);
 macro bool @is_floatlike(#value) => types::is_floatlike($typeof(#value));
 macro bool @is_float(#value) => types::is_float($typeof(#value));
 macro bool @is_promotable_to_floatlike(#value) => types::is_promotable_to_floatlike($typeof(#value));
 macro bool @is_promotable_to_float(#value) => types::is_promotable_to_float($typeof(#value));
+macro bool @is_vector(#value) => types::is_vector($typeof(#value));
 macro bool @is_same_vector_type(#value1, #value2) => types::is_same_vector_type($typeof(#value1), $typeof(#value2));
+macro bool @assign_to(#value1, #value2) => $assignable(#value1, $typeof(#value2));
+
 macro promote_int(x)
 {
-	$if (@is_int(x))
+	$if @is_int(x):
 		return (double)x;
 	$else
 		return x;
@@ -20,3 +27,4 @@ macro promote_int(x)
 }

 macro TypeKind @inner_kind(#value) => types::inner_kind($typeof(#value));
+
--- a/lib/std/core/varstring.c3
+++ b/lib/std/core/varstring.c3
@@ -1,327 +0,0 @@
-module std::core::string;
-import libc;
-
-typedef VarString = distinct void*;
-typedef DynStr = VarString;
-typedef DynString = VarString;
-typedef VString = VarString;
-typedef Text = VarString;
-
-const usz MIN_CAPACITY = 16;
-
-fn VarString new_with_capacity(usz capacity, Allocator* allocator = mem::heap())
-{
-	if (capacity < MIN_CAPACITY) capacity = MIN_CAPACITY;
-	StringData* data = malloc(StringData, 1, .using = allocator, .end_padding = capacity);
-	data.allocator = allocator;
-	data.len = 0;
-	data.capacity = capacity;
-	return (VarString)data;
-}
-
-fn VarString new(String c)
-{
-	usz len = c.len;
-	VarString str = new_with_capacity(len);
-	StringData* data = str.data();
-	if (len)
-	{
-		data.len = len;
-		mem::copy(&data.chars, c.ptr, len);
-	}
-	return (VarString)data;
-}
-
-fn ZString VarString.zstr(VarString str)
-{
-	StringData* data = str.data();
-	if (!data) return (ZString)"";
-	if (data.capacity == data.len)
-	{
-		str.reserve(1);
-		data.chars[data.len] = 0;
-	}
-	else if (data.chars[data.len] != 0)
-	{
-		data.chars[data.len] = 0;
-	}
-	return (ZString)&data.chars[0];
-}
-
-fn usz VarString.capacity(VarString this)
-{
-	if (!this) return 0;
-	return this.data().capacity;
-}
-
-fn usz VarString.len(VarString this)
-{
-	if (!this) return 0;
-	return this.data().len;
-}
-
-/**
- * @require new_size <= this.len()
- */
-fn void VarString.chop(VarString this, usz new_size)
-{
-	if (!this) return;
-	this.data().len = new_size;
-}
-
-fn String VarString.str(VarString str)
-{
-	StringData* data = (StringData*)str;
-	if (!data) return "";
-	return (String)data.chars[:data.len];
-}
-
-fn void VarString.append_utf32(VarString* str, Char32[] chars)
-{
-	str.reserve(chars.len);
-	foreach (Char32 c : chars)
-	{
-		str.append_char32(c);
-	}
-}
-
-/**
- * @require index < str.len()
- **/
-fn void VarString.set(VarString str, usz index, char c)
-{
-	str.data().chars[index] = c;
-}
-
-fn void VarString.append_repeat(VarString* str, char c, usz times)
-{
-	if (times == 0) return;
-	str.reserve(times);
-	StringData* data = str.data();
-	for (usz i = 0; i < times; i++)
-	{
-        data.chars[data.len++] = c;
-	}
-}
-
-/**
- * @require c <= 0x10ffff
- */
-fn void VarString.append_char32(VarString* str, Char32 c)
-{
-	if (c < 0x7f)
-	{
-		str.reserve(1);
-		StringData* data = str.data();
-        data.chars[data.len++] = (char)c;
-        return;
-    }
-    if (c < 0x7ff)
-    {
-		str.reserve(2);
-		StringData* data = str.data();
-		data.chars[data.len++] = (char)(0xC0 | c >> 6);
-        data.chars[data.len++] = (char)(0x80 | (c & 0x3F));
-        return;
-    }
-    if (c < 0xffff)
-    {
-		str.reserve(3);
-		StringData* data = str.data();
-		data.chars[data.len++] = (char)(0xE0 | c >> 12);
-        data.chars[data.len++] = (char)(0x80 | (c >> 6 & 0x3F));
-        data.chars[data.len++] = (char)(0x80 | (c & 0x3F));
-        return;
-    }
-	str.reserve(4);
-	StringData* data = str.data();
-	data.chars[data.len++] = (char)(0xF0 | c >> 18);
-    data.chars[data.len++] = (char)(0x80 | (c >> 12 & 0x3F));
-    data.chars[data.len++] = (char)(0x80 | (c >> 6 & 0x3F));
-    data.chars[data.len++] = (char)(0x80 | (c & 0x3F));
-}
-
-fn VarString VarString.tcopy(VarString* str) => str.copy(mem::temp());
-
-fn VarString VarString.copy(VarString* str, Allocator* allocator = null)
-{
-	if (!str)
-	{
-		if (allocator) return new_with_capacity(0, allocator);
-		return (VarString)null;
-	}
-	if (!allocator) allocator = mem::heap();
-	StringData* data = str.data();
-	VarString new_string = new_with_capacity(data.capacity, allocator);
-	mem::copy((char*)new_string.data(), (char*)data, StringData.sizeof + data.len);
-	return new_string;
-}
-
-fn ZString VarString.copy_zstr(VarString* str, Allocator* allocator = mem::heap())
-{
-	usz str_len = str.len();
-	if (!str_len)
-	{
-		return (ZString)calloc(1, .using = allocator);
-	}
-	char* zstr = malloc(str_len + 1, .using = allocator);
-	StringData* data = str.data();
-	mem::copy(zstr, &data.chars, str_len);
-	zstr[str_len] = 0;
-	return (ZString)zstr;
-}
-
-fn String VarString.copy_str(VarString* str, Allocator* allocator = mem::heap())
-{
-	return (String)str.copy_zstr(allocator)[:str.len()];
-}
-
-fn String VarString.tcopy_str(VarString* str) => str.copy_str(mem::temp()) @inline;
-
-fn bool VarString.equals(VarString str, VarString other_string)
-{
-	StringData *str1 = str.data();
-	StringData *str2 = other_string.data();
-	if (str1 == str2) return true;
-	if (!str1) return str2.len == 0;
-	if (!str2) return str1.len == 0;
-	usz str1_len = str1.len;
-	if (str1_len != str2.len) return false;
-	for (int i = 0; i < str1_len; i++)
-	{
-		if (str1.chars[i] != str2.chars[i]) return false;
-	}
-	return true;
-}
-
-fn void VarString.destroy(VarString* str)
-{
-	if (!*str) return;
-	StringData* data = str.data();
-	if (!data) return;
-	free(data, .using = data.allocator);
-	*str = (VarString)null;
-}
-
-fn bool VarString.less(VarString str, VarString other_string)
-{
-	StringData* str1 = str.data();
-	StringData* str2 = other_string.data();
-	if (str1 == str2) return false;
-	if (!str1) return str2.len != 0;
-	if (!str2) return str1.len == 0;
-	usz str1_len = str1.len;
-	usz str2_len = str2.len;
-	if (str1_len != str2_len) return str1_len < str2_len;
-	for (int i = 0; i < str1_len; i++)
-	{
-		if (str1.chars[i] >= str2.chars[i]) return false;
-	}
-	return true;
-}
-
-fn void VarString.append_chars(VarString* this, String str)
-{
-	usz other_len = str.len;
-	if (!other_len) return;
-	if (!*this)
-	{
-		*this = new(str);
-		return;
-	}
-	this.reserve(other_len);
-	StringData* data = (StringData*)*this;
-	mem::copy(&data.chars[data.len], str.ptr, other_len);
-	data.len += other_len;
-}
-
-fn Char32[] VarString.copy_utf32(VarString* this, Allocator* allocator = mem::heap())
-{
-	return str::utf8to32(this.str(), allocator) @inline!!;
-}
-
-fn void VarString.append_string(VarString* this, VarString str)
-{
-	StringData* other = (StringData*)str;
-	if (!other) return;
-	this.append(str.str());
-}
-
-fn void VarString.clear(VarString* str)
-{
-	str.data().len = 0;
-}
-
-fn void VarString.append_char(VarString* str, char c)
-{
-	if (!*str)
-	{
-		*str = new_with_capacity(MIN_CAPACITY);
-	}
-	str.reserve(1);
-	StringData* data = (StringData*)*str;
-	data.chars[data.len++] = c;
-}
-
-
-macro void VarString.append(VarString* str, value)
-{
-	var $Type = $typeof(value);
-	$switch ($Type)
-		$case char:
-		$case ichar:
-			str.append_char(value);
-		$case VarString:
-			str.append_string(value);
-		$case String:
-			str.append_chars(value);
-		$case Char32:
-			str.append_char32(value);
-		$default:
-			$switch
-				$case @convertible(value, Char32):
-					str.append_char32(value);
-				$case @convertible(value, String):
-					str.append_chars(value);
-				$default:
-					$assert(false, "Unsupported type for append – use printf instead.");
-			$endswitch
-	$endswitch
-}
-
-
-fn StringData* VarString.data(VarString str) @inline @private
-{
-	return (StringData*)str;
-}
-
-fn void VarString.reserve(VarString* str, usz addition) @private
-{
-	StringData* data = str.data();
-	if (!data)
-	{
-		*str = string::new_with_capacity(addition);
-		return;
-	}
-	usz len = data.len + addition;
-	if (data.capacity >= len) return;
-	usz new_capacity = data.capacity *= 2;
-	if (new_capacity < MIN_CAPACITY) new_capacity = MIN_CAPACITY;
-	*str = (VarString)realloc(data, StringData.sizeof + new_capacity, .using = data.allocator);
-}
-
-fn VarString VarString.new_concat(VarString a, VarString b, Allocator* allocator = mem::heap())
-{
-	VarString string = new_with_capacity(a.len() + b.len(), allocator);
-	string.append(a);
-	string.append(b);
-	return string; 
-}
-
-struct StringData @private
-{
-	Allocator* allocator;
-	usz len;
-	usz capacity;
-	char[*] chars;
-}
--- a/lib/std/crypto/rc4.c3
+++ b/lib/std/crypto/rc4.c3
@@ -12,36 +12,34 @@ struct Rc4
 /**
 * Initialize the RC4 state.
 *
- * @param [inout] this "The RC4 state"
 * @param [in] key "The key to use"
 * @require key.len > 0 "The key must be at least 1 byte long"
 **/
-fn void Rc4.init(Rc4* this, char[] key)
+fn void Rc4.init(&self, char[] key)
 {
 	// Init the state matrix
-	foreach (char i, &c : this.state) *c = i;
+	foreach (char i, &c : self.state) *c = i;
 	for (int i = 0, int j = 0; i < 256; i++)
 	{
-		j = (j + this.state[i] + key[i % key.len]) & 0xFF;
-		@swap(this.state[i], this.state[j]);
+		j = (j + self.state[i] + key[i % key.len]) & 0xFF;
+		@swap(self.state[i], self.state[j]);
 	}
-	this.i = 0;
-	this.j = 0;
+	self.i = 0;
+	self.j = 0;
 }

 /**
 * Encrypt or decrypt a sequence of bytes.
 *
- * @param [inout] this "The RC4 State"
 * @param [in] in "The input"
 * @param [out] out "The output"
 * @require in.len <= out.len "Output would overflow"
 **/
-fn void Rc4.crypt(Rc4* this, char[] in, char[] out)
+fn void Rc4.crypt(&self, char[] in, char[] out)
 {
-	uint i = this.i;
-	uint j = this.j;
-	char* state = &this.state;
+	uint i = self.i;
+	uint j = self.j;
+	char* state = &self.state;
 	isz len = in.len;
 	foreach (idx, c : in)
 	{
@@ -50,16 +48,16 @@ fn void Rc4.crypt(Rc4* this, char[] in, char[] out)
 		@swap(state[i], state[j]);
 		out[idx] = in[idx] ^ state[(state[i] + state[j]) & 0xFF];
 	}
-	this.i = i;
-	this.j = j;
+	self.i = i;
+	self.j = j;
 }

 /**
 * Clear the rc4 state.
 *
- * @param [out] this "The RC4 State"
+ * @param [&out] self "The RC4 State"
 **/
-fn void Rc4.destroy(Rc4* this)
+fn void Rc4.destroy(&self)
 {
-	*this = {};
+	*self = {};
 }
--- a/lib/std/encoding/base64.c3
+++ b/lib/std/encoding/base64.c3
@@ -0,0 +1,288 @@
+module std::encoding::base64;
+import std::core::bitorder;
+
+// The implementation is based on https://www.rfc-editor.org/rfc/rfc4648
+// Specifically this section:
+// https://www.rfc-editor.org/rfc/rfc4648#section-4
+
+const STD_ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+const URL_ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
+
+const MASK @private = 0b111111;
+
+struct Base64Encoder
+{
+	int padding;
+	String alphabet;
+}
+
+fault Base64Error
+{
+	DUPLICATE_IN_ALPHABET,
+	PADDING_IN_ALPHABET,
+	DESTINATION_TOO_SMALL,
+	INVALID_PADDING,
+	INVALID_CHARACTER,
+}
+
+/**
+ * @param alphabet "The alphabet used for encoding."
+ * @param padding "Set to a negative value to disable padding."
+ * @require alphabet.len == 64
+ * @require padding < 256
+ * @return! Base64Error.DUPLICATE_IN_ALPHABET, Base64Error.PADDING_IN_ALPHABET
+ **/
+fn void! Base64Encoder.init(&self, String alphabet, int padding = '=')
+{
+	check_alphabet(alphabet, padding)!;
+	*self = { .padding = padding, .alphabet = alphabet };
+}
+
+/**
+ * Calculate the size of the encoded data.
+ * @param n "Size of the input to be encoded."
+ * @return "The size of the input once encoded."
+ **/
+fn usz Base64Encoder.encode_len(&self, usz n)
+{
+	if (self.padding >= 0) return (n + 2) / 3 * 4;
+	usz trailing = n % 3;
+	return n / 3 * 4 + (trailing * 4 + 2) / 3;
+}
+
+/**
+ * Encode the content of src into dst, which must be properly sized.
+ * @param src "The input to be encoded."
+ * @param dst "The encoded input."
+ * @return "The encoded size."
+ * @return! Base64Error.DESTINATION_TOO_SMALL
+ **/
+fn usz! Base64Encoder.encode(&self, char[] src, char[] dst)
+{
+	if (src.len == 0) return 0;
+	usz dn = self.encode_len(src.len);
+	if (dst.len < dn) return Base64Error.DESTINATION_TOO_SMALL?;
+	usz trailing = src.len % 3;
+	char[] src3 = src[:^trailing];
+
+	while (src3.len > 0)
+	{
+		uint group = (uint)src3[0] << 16 | (uint)src3[1] << 8 | (uint)src3[2];
+		dst[0] = self.alphabet[group >> 18 & MASK];
+		dst[1] = self.alphabet[group >> 12 & MASK];
+		dst[2] = self.alphabet[group >> 6 & MASK];
+		dst[3] = self.alphabet[group & MASK];
+		dst = dst[4..];
+		src3 = src3[3..];
+	}
+
+	// Encode the remaining bytes according to:
+	// https://www.rfc-editor.org/rfc/rfc4648#section-3.5
+	switch (trailing)
+	{
+		case 1:
+			uint group = (uint)src[^1] << 16;
+			dst[0] = self.alphabet[group >> 18 & MASK];
+			dst[1] = self.alphabet[group >> 12 & MASK];
+			if (self.padding >= 0)
+			{
+				char pad = (char)self.padding;
+				dst[2] = pad;
+				dst[3] = pad;
+			}
+		case 2:
+			uint group = (uint)src[^2] << 16 | (uint)src[^1] << 8;
+			dst[0] = self.alphabet[group >> 18 & MASK];
+			dst[1] = self.alphabet[group >> 12 & MASK];
+			dst[2] = self.alphabet[group >> 6 & MASK];
+			if (self.padding >= 0)
+			{
+				char pad = (char)self.padding;
+				dst[3] = pad;
+			}
+	}
+	return dn;
+}
+
+struct Base64Decoder
+{
+	int padding;
+	String alphabet;
+	char[256] reverse;
+	char invalid;
+}
+
+/**
+ * @param alphabet "The alphabet used for encoding."
+ * @param padding "Set to a negative value to disable padding."
+ * @require alphabet.len == 64
+ * @require padding < 256
+ * @return! Base64Error.DUPLICATE_IN_ALPHABET, Base64Error.PADDING_IN_ALPHABET
+ **/
+fn void! Base64Decoder.init(&self, String alphabet, int padding = '=')
+{
+	check_alphabet(alphabet, padding)!;
+	*self = { .padding = padding, .alphabet = alphabet };
+
+	bool[256] checked;
+	foreach (i, c : alphabet)
+	{
+		checked[c] = true;
+		self.reverse[c] = (char)i;
+	}
+	if (padding < 0)
+	{
+		self.invalid = 255;
+		return;
+	}
+	// Find a character for invalid neither in the alphabet nor equal to the padding.
+	char pad = (char)padding;
+	foreach (i, ok : checked)
+	{
+		if (!ok && (char)i != pad)
+		{
+			self.invalid = (char)i;
+			break;
+		}
+	}
+}
+
+/**
+ * Calculate the size of the decoded data.
+ * @param n "Size of the input to be decoded."
+ * @return "The size of the input once decoded."
+ * @return! Base64Error.INVALID_PADDING
+ **/
+fn usz! Base64Decoder.decode_len(&self, usz n)
+{
+	usz dn = n / 4 * 3;
+	usz trailing = n % 4;
+	if (self.padding >= 0)
+	{
+		if (trailing != 0) return Base64Error.INVALID_PADDING?;
+		// source size is multiple of 4
+	}
+	else
+	{
+		if (trailing == 1) return Base64Error.INVALID_PADDING?;
+		dn += trailing * 3 / 4;
+	}
+	return dn;
+}
+
+/**
+ * Decode the content of src into dst, which must be properly sized.
+ * @param src "The input to be decoded."
+ * @param dst "The decoded input."
+ * @return "The decoded size."
+ * @return! Base64Error.DESTINATION_TOO_SMALL, Base64Error.INVALID_PADDING, Base64Error.INVALID_CHARACTER
+ **/
+fn usz! Base64Decoder.decode(&self, char[] src, char[] dst)
+{
+	if (src.len == 0) return 0;
+	usz dn = self.decode_len(src.len)!;
+	if (dst.len < dn) return Base64Error.DESTINATION_TOO_SMALL?;
+
+	usz trailing = src.len % 4;
+	char[] src4 = src;
+	switch
+	{
+		case self.padding < 0:
+			src4 = src[:^trailing];
+		default:
+			// If there is padding, keep the last 4 bytes for later.
+			// NB. src.len >= 4 as decode_len passed
+			trailing = 4;
+			char pad = (char)self.padding;
+			if (src[^1] == pad) src4 = src[:^4];
+	}
+	while (src4.len > 0)
+	{
+		char c0 = self.reverse[src4[0]];
+		char c1 = self.reverse[src4[1]];
+		char c2 = self.reverse[src4[2]];
+		char c3 = self.reverse[src4[3]];
+		switch (self.invalid)
+		{
+			case c0:
+			case c1:
+			case c2:
+			case c3:
+				return Base64Error.INVALID_CHARACTER?;
+		}
+		uint group = (uint)c0 << 18 | (uint)c1 << 12 | (uint)c2 << 6 | (uint)c3;
+		dst[0] = (char)(group >> 16);
+		dst[1] = (char)(group >> 8);
+		dst[2] = (char)group;
+		dst = dst[3..];
+		src4 = src4[4..];
+	}
+
+	if (trailing == 0) return dn;
+
+	src = src[^trailing..];
+	char c0 = self.reverse[src[0]];
+	char c1 = self.reverse[src[1]];
+	if (c0 == self.invalid || c1 == self.invalid) return Base64Error.INVALID_PADDING?;
+	if (self.padding < 0)
+	{
+		switch (src.len)
+		{
+			case 2:
+				uint group = (uint)c0 << 18 | (uint)c1 << 12;
+				dst[0] = (char)(group >> 16);
+			case 3:
+				char c2 = self.reverse[src[2]];
+				if (c2 == self.invalid) return Base64Error.INVALID_CHARACTER?;
+				uint group = (uint)c0 << 18 | (uint)c1 << 12 | (uint)c2 << 6;
+				dst[0] = (char)(group >> 16);
+				dst[1] = (char)(group >> 8);
+		}
+	}
+	else
+	{
+		// Valid paddings are:
+		// 2: xx==
+		// 1: xxx=
+		char pad = (char)self.padding;
+		switch (pad)
+		{
+			case src[2]:
+				if (src[3] != pad) return Base64Error.INVALID_PADDING?;
+				uint group = (uint)c0 << 18 | (uint)c1 << 12;
+				dst[0] = (char)(group >> 16);
+				dn -= 2;
+			case src[3]:
+				char c2 = self.reverse[src[2]];
+				if (c2 == self.invalid) return Base64Error.INVALID_CHARACTER?;
+				uint group = (uint)c0 << 18 | (uint)c1 << 12 | (uint)c2 << 6;
+				dst[0] = (char)(group >> 16);
+				dst[1] = (char)(group >> 8);
+				dn -= 1;
+		}
+	}
+	return dn;
+}
+
+// Make sure that all bytes in the alphabet are unique and
+// the padding is not present in the alphabet.
+fn void! check_alphabet(String alphabet, int padding) @local
+{
+	bool[256] checked;
+	if (padding < 0)
+	{
+		foreach (c : alphabet)
+		{
+			if (checked[c]) return Base64Error.DUPLICATE_IN_ALPHABET?;
+			checked[c] = true;
+		}
+		return;
+	}
+	char pad = (char)padding;
+	foreach (c : alphabet)
+	{
+		if (c == pad) return Base64Error.PADDING_IN_ALPHABET?;
+		if (checked[c]) return Base64Error.DUPLICATE_IN_ALPHABET?;
+		checked[c] = true;
+	}
+}
--- a/lib/std/encoding/csv.c3
+++ b/lib/std/encoding/csv.c3
@@ -0,0 +1,64 @@
+module std::encoding::csv;
+import std::io;
+
+struct CsvReader
+{
+	InStream* stream;
+	String separator;
+}
+
+fn void CsvReader.init(&self, InStream* stream, String separator = ",")
+{
+	self.stream = stream;
+	self.separator = separator;
+}
+
+fn String[]! CsvReader.read_new_row(self, Allocator* allocator = mem::heap())
+{
+	return self.read_new_row_with_allocator(mem::temp()) @inline;
+}
+
+fn String[]! CsvReader.read_new_row_with_allocator(self, Allocator* allocator = mem::heap())
+{
+	@pool(allocator)
+	{
+		return io::treadline(self.stream).split(self.separator, .allocator = allocator);
+	};
+}
+
+fn String[]! CsvReader.read_temp_row(self)
+{
+	return self.read_new_row_with_allocator(mem::temp()) @inline;
+}
+
+fn void! CsvReader.skip_row(self) @maydiscard
+{
+	@pool()
+	{
+		(void)io::treadline(self.stream);
+	};
+}
+
+macro CsvReader.@each_row(self, int rows = int.max; @body(String[] row))
+{
+	InputStream* stream = self.stream;
+	String sep = self.separator;
+	while (rows--)
+	{
+		@stack_mem(512; Allocator* mem)
+		{
+			String[] parts;
+			@pool()
+			{
+				String! s = stream.treadline();
+				if (catch err = s)
+				{
+					if (err == IoError.EOF) return;
+					return err?;
+				}
+				parts = s.split(sep, .allocator = mem);
+			};
+			@body(parts);
+		};
+	}
+}
--- a/lib/std/encoding/json.c3
+++ b/lib/std/encoding/json.c3
@@ -6,7 +6,25 @@ import std::io;
 import std::ascii;
 import std::collections::object;

-enum JsonTokenType
+fault JsonParsingError
+{
+	EOF,
+	UNEXPECTED_CHARACTER,
+	INVALID_ESCAPE_SEQUENCE,
+	DUPLICATE_MEMBERS,
+	INVALID_NUMBER,
+}
+
+fn Object*! parse(InStream* s, Allocator* allocator = mem::heap())
+{
+	JsonContext context = { .last_string = dstring::new_with_capacity(64, allocator), .stream = s, .allocator = allocator };
+	defer context.last_string.free();
+	return parse_any(&context);
+}
+
+// -- Implementation follows --
+
+enum JsonTokenType @local
 {
 	NO_TOKEN,
 	LBRACE,
@@ -23,79 +41,67 @@ enum JsonTokenType
 	EOF,
 }

-struct JsonParser
+struct JsonContext @local
 {
 	uint line;
-	Stream stream;
+	InStream* stream;
 	Allocator* allocator;
 	JsonTokenType token;
 	DString last_string;
 	double last_number;
 	char current;
-	anyerr current_err;
-	bool skip_comments;
-	bool reached_end;
+	bitstruct : char {
+		bool skip_comments;
+		bool reached_end;
+		bool pushed_back;
+	}
 }

-fault JsonParsingError
-{
-	EOF,
-	UNEXPECTED_CHARACTER,
-	INVALID_ESCAPE_SEQUENCE,
-	DUPLICATE_MEMBERS,
-	INVALID_NUMBER,
-}

-fn void JsonParser.init(JsonParser* parser, Stream s, Allocator* using = mem::heap())
-{
-	*parser = { .last_string = dstring::new_with_capacity(64, using), .stream = s, .allocator = using };
-}
-
-fn Object*! JsonParser.parse_from_token(JsonParser* this, JsonTokenType token)
+fn Object*! parse_from_token(JsonContext* context, JsonTokenType token) @local
 {
 	switch (token)
 	{
 		case NO_TOKEN: unreachable();
-		case LBRACE: return this.parse_map();
-		case LBRACKET: return this.parse_array();
+		case LBRACE: return parse_map(context);
+		case LBRACKET: return parse_array(context);
 		case COMMA:
 		case RBRACE:
 		case RBRACKET:
-		case COLON: return JsonParsingError.UNEXPECTED_CHARACTER!;
-		case STRING: return object::new_string(this.last_string.str(), this.allocator);
-		case NUMBER: return object::new_float(this.last_number, this.allocator);
+		case COLON: return JsonParsingError.UNEXPECTED_CHARACTER?;
+		case STRING: return object::new_string(context.last_string.str_view(), context.allocator);
+		case NUMBER: return object::new_float(context.last_number, context.allocator);
 		case TRUE: return object::new_bool(true);
 		case FALSE: return object::new_bool(false);
 		case NULL: return object::new_null();
-		case EOF: return JsonParsingError.EOF!;
+		case EOF: return JsonParsingError.EOF?;
 	}
-	unreachable();
 }
-fn Object*! JsonParser.parse_any(JsonParser* this)
+fn Object*! parse_any(JsonContext* context) @local
 {
-	return this.parse_from_token(this.advance());
+	return parse_from_token(context, advance(context));
 }

-fn JsonTokenType! JsonParser.lex_number(JsonParser* this, char c)
+fn JsonTokenType! lex_number(JsonContext *context, char c) @local
 {
 	@pool()
 	{
-		DString t = dstring::tnew_with_capacity(32);
+		DString t = dstring::temp_with_capacity(32);
 		bool negate = c == '-';
 		if (negate)
 		{
 			t.append(c);
-			c = this.read_next()?;
+			c = read_next(context)!;
 		}
-		while (c >= '0' && c <= '9')
+		while (c.is_digit())
 		{
 			t.append(c);
-			c = this.read_next()?;
+			c = read_next(context)!;
 		}
 		if (c == '.')
 		{
 			t.append(c);
-			while (c = this.read_next()?, c >= '0' && c <= '9')
+			while (c = read_next(context)!, c.is_digit())
 			{
 				t.append(c);
 			}
@@ -103,113 +109,123 @@ fn JsonTokenType! JsonParser.lex_number(JsonParser* this, char c)
 		if ((c | 32) == 'e')
 		{
 			t.append(c);
-			c = this.read_next()?;
+			c = read_next(context)!;
 			switch (c)
 			{
 				case '-':
 				case '+':
 					t.append(c);
-					c = this.read_next()?;
+					c = read_next(context)!;
 			}
-			if (c < '0' || c > '9') return JsonParsingError.INVALID_NUMBER!;
-			while (c >= '0' && c <= '9')
+			if (!c.is_digit()) return JsonParsingError.INVALID_NUMBER?;
+			while (c.is_digit())
 			{
 				t.append(c);
-				c = this.read_next()?;
+				c = read_next(context)!;
 			}
 		}
-		this.pushback();
-		double! d = str::to_double(t.str()) ?? JsonParsingError.INVALID_NUMBER!;
-		this.last_number = d?;
+		pushback(context, c);
+		double! d = t.str_view().to_double() ?? JsonParsingError.INVALID_NUMBER?;
+		context.last_number = d!;
 		return NUMBER;
 	};
 }

-fn Object*! JsonParser.parse_map(JsonParser* this)
+fn Object*! parse_map(JsonContext* context) @local
 {
-	Object* map = object::new_obj(this.allocator);
-	JsonTokenType token = this.advance()?;
+	Object* map = object::new_obj(context.allocator);
+	JsonTokenType token = advance(context)!;
 	defer catch map.free();

-	DString temp_key = dstring::new_with_capacity(32, this.allocator);
+	DString temp_key = dstring::new_with_capacity(32, context.allocator);
 	defer temp_key.free();
 	while (token != JsonTokenType.RBRACE)
 	{
-		if (token != JsonTokenType.STRING) return JsonParsingError.UNEXPECTED_CHARACTER!;
-        DString string = this.last_string;
-        if (map.has_key(string.str())) return JsonParsingError.DUPLICATE_MEMBERS!;
-        // Copy the key to our temp holder. We do this to work around the issue
-        // if the temp allocator should be used as the default allocator.
-        temp_key.clear();
-        temp_key.append(string);
-        this.parse_expected(COLON)?;
-        Object* element = this.parse_any()?;
-		map.set(temp_key.str(), element);
-        token = this.advance()?;
-        if (token == JsonTokenType.COMMA)
-        {
-            token = this.advance()?;
-            continue;
-        }
-        if (token != JsonTokenType.RBRACE) return JsonParsingError.UNEXPECTED_CHARACTER!;
+		if (token != JsonTokenType.STRING) return JsonParsingError.UNEXPECTED_CHARACTER?;
+		DString string = context.last_string;
+		if (map.has_key(string.str_view())) return JsonParsingError.DUPLICATE_MEMBERS?;
+		// Copy the key to our temp holder. We do this to work around the issue
+		// if the temp allocator should be used as the default allocator.
+		temp_key.clear();
+		temp_key.append(string);
+		parse_expected(context, COLON)!;
+		Object* element = parse_any(context)!;
+		map.set(temp_key.str_view(), element);
+		token = advance(context)!;
+		if (token == JsonTokenType.COMMA)
+		{
+			token = advance(context)!;
+			continue;
+		}
+		if (token != JsonTokenType.RBRACE) return JsonParsingError.UNEXPECTED_CHARACTER?;
 	}
 	return map;
 }

-fn Object*! JsonParser.parse_array(JsonParser* this)
+fn Object*! parse_array(JsonContext* context) @local
 {
-	Object* list = object::new_obj(this.allocator);
+	Object* list = object::new_obj(context.allocator);
 	defer catch list.free();
-	JsonTokenType token = this.advance()?;
+	JsonTokenType token = advance(context)!;
 	while (token != JsonTokenType.RBRACKET)
 	{
-		Object* element = this.parse_from_token(token)?;
+		Object* element = parse_from_token(context, token)!;
 		list.append(element);
-		token = this.advance()?;
+		token = advance(context)!;
 		if (token == JsonTokenType.COMMA)
 		{
-			token = this.advance()?;
-		    continue;
+			token = advance(context)!;
+			continue;
 		}
-		if (token != JsonTokenType.RBRACKET) return JsonParsingError.UNEXPECTED_CHARACTER!;
+		if (token != JsonTokenType.RBRACKET) return JsonParsingError.UNEXPECTED_CHARACTER?;
 	}
 	return list;
 }

-fn void JsonParser.pushback(JsonParser* this)
+fn void pushback(JsonContext* context, char c) @local
 {
-	if (!this.reached_end) this.stream.pushback_byte()!!;
+	if (!context.reached_end)
+	{
+		assert(!context.pushed_back);
+		context.pushed_back = true;
+		context.current = c;
+	}
 }

-fn char! JsonParser.read_next(JsonParser* this)
+fn char! read_next(JsonContext* context) @local
 {
-	if (this.reached_end) return '\0';
-	char! c = this.stream.read_byte();
+	if (context.reached_end) return '\0';
+	if (context.pushed_back)
+	{
+		context.pushed_back = false;
+		return context.current;
+	}
+	char! c = context.stream.read_byte();
 	if (catch err = c)
 	{
 		case IoError.EOF:
-			this.reached_end = true;
+			context.reached_end = true;
 			return '\0';
 		default:
-			return err!;
+			return err?;
 	}
 	if (c == 0)
 	{
-		this.reached_end = true;
+		context.reached_end = true;
 	}
 	return c;
 }

-fn JsonTokenType! JsonParser.advance(JsonParser* this)
+fn JsonTokenType! advance(JsonContext* context) @local
 {
 	char c;
 	// Skip whitespace
-	while WS: (c = this.read_next()?)
+	while WS: (c = read_next(context)!)
 	{
 		switch (c)
 		{
 			case '\n':
-				this.line++;
+				context.line++;
 				nextcase;
 			case ' ':
 			case '\t':
@@ -217,24 +233,24 @@ fn JsonTokenType! JsonParser.advance(JsonParser* this)
 			case '\v':
 				continue;
 			case '/':
-				if (!this.skip_comments) break;
-				c = this.read_next()?;
+				if (!context.skip_comments) break;
+				c = read_next(context)!;
 				if (c != '*')
 				{
-					this.pushback();
+					pushback(context, c);
 					break WS;
 				}
-				while COMMENT: (1)
+				while COMMENT: (true)
 				{
 					// Skip to */
-					while (c = this.read_next()?)
+					while (c = read_next(context)!)
 					{
-						if (c == '\n') this.line++;
+						if (c == '\n') context.line++;
 						if (c != '*') continue;
 						// Skip through all the '*'
-						while (c = this.read_next()?)
+						while (c = read_next(context)!)
 						{
-							if (c == '\n') this.line++;
+							if (c == '\n') context.line++;
 							if (c != '*') break;
 						}
 						if (c == '/') break COMMENT;
@@ -248,7 +264,7 @@ fn JsonTokenType! JsonParser.advance(JsonParser* this)
 	switch (c)
 	{
 		case '\0':
-			return IoError.EOF!;
+			return IoError.EOF?;
 		case '{':
 			return LBRACE;
 		case '}':
@@ -262,65 +278,65 @@ fn JsonTokenType! JsonParser.advance(JsonParser* this)
 		case ',':
 			return COMMA;
 		case '"':
-			return this.lex_string();
+			return lex_string(context);
 		case '-':
 		case '0'..'9':
-			return this.lex_number(c);
+			return lex_number(context, c);
 		case 't':
-			this.match("rue")?;
+			match(context, "rue")!;
 			return TRUE;
 		case 'f':
-			this.match("alse")?;
+			match(context, "alse")!;
 			return FALSE;
 		case 'n':
-			this.match("ull")?;
+			match(context, "ull")!;
 			return NULL;
 		default:
-			return JsonParsingError.UNEXPECTED_CHARACTER!;
+			return JsonParsingError.UNEXPECTED_CHARACTER?;
 	}
 }

-fn void! JsonParser.match(JsonParser* this, String str)
+fn void! match(JsonContext* context, String str) @local
 {
 	foreach (c : str)
 	{
-		char l = this.read_next()?;
-		if (l != c) return JsonParsingError.UNEXPECTED_CHARACTER!;
+		char l = read_next(context)!;
+		if (l != c) return JsonParsingError.UNEXPECTED_CHARACTER?;
 	}
 }

-fn void! JsonParser.parse_expected(JsonParser* this, JsonTokenType token) @local
+fn void! parse_expected(JsonContext* context, JsonTokenType token) @local
 {
-	if (this.advance()? != token) return JsonParsingError.UNEXPECTED_CHARACTER!;
+	if (advance(context)! != token) return JsonParsingError.UNEXPECTED_CHARACTER?;
 }

-fn JsonTokenType! JsonParser.lex_string(JsonParser *this)
+fn JsonTokenType! lex_string(JsonContext* context)
 {
-	this.last_string.clear();
-	while LOOP: (1)
+	context.last_string.clear();
+	while LOOP: (true)
 	{
-		char c = this.read_next()?;
+		char c = read_next(context)!;
 		switch (c)
 		{
 			case '\0':
-				return JsonParsingError.EOF!;
+				return JsonParsingError.EOF?;
 			case 1..31:
-				return JsonParsingError.UNEXPECTED_CHARACTER!;
+				return JsonParsingError.UNEXPECTED_CHARACTER?;
 			case '"':
 				break LOOP;
 			case '\\':
 				break;
 			default:
-				this.last_string.append(c);
+				context.last_string.append(c);
 				continue;
 		}
-		c = this.read_next()?;
+		c = read_next(context)!;
 		switch (c)
 		{
 			case '\0':
-				return JsonParsingError.EOF!;
+				return JsonParsingError.EOF?;
 			case 1..31:
-				return JsonParsingError.UNEXPECTED_CHARACTER!;
+				return JsonParsingError.UNEXPECTED_CHARACTER?;
 			case '"':
 			case '\\':
 			case '/':
@@ -339,14 +355,14 @@ fn JsonTokenType! JsonParser.lex_string(JsonParser *this)
 				uint val;
 				for (int i = 0; i < 4; i++)
 				{
-					c = this.read_next()?;
-					if (!c.is_xdigit()) return JsonParsingError.INVALID_ESCAPE_SEQUENCE!;
+					c = read_next(context)!;
+					if (!c.is_xdigit()) return JsonParsingError.INVALID_ESCAPE_SEQUENCE?;
 					val = val << 4 + (c > '9' ? (c | 32) - 'a' + 10 : c - '0');
 				}
-				this.last_string.append_char32(val);
+				context.last_string.append_char32(val);
 				continue;
 			default:
-				 return JsonParsingError.INVALID_ESCAPE_SEQUENCE!;
+				 return JsonParsingError.INVALID_ESCAPE_SEQUENCE?;
 		}
 	}
 	return STRING;
--- a/lib/std/hash/adler32.c3
+++ b/lib/std/hash/adler32.c3
@@ -8,46 +8,46 @@ const uint ADLER_CONST @private = 65521;

 struct Adler32
 {
-    uint a;
-    uint b;
+	uint a;
+	uint b;
 }

-fn void Adler32.init(Adler32 *this)
+fn void Adler32.init(&self)
 {
-    *this = { 1, 0 };
+	*self = { 1, 0 };
 }

-fn void Adler32.updatec(Adler32* this, char c)
+fn void Adler32.updatec(&self, char c)
 {
-    this.a = (this.a + c) % ADLER_CONST;
-    this.b = (this.b + this.a) % ADLER_CONST;
+	self.a = (self.a + c) % ADLER_CONST;
+	self.b = (self.b + self.a) % ADLER_CONST;
 }

-fn void Adler32.update(Adler32* this, char[] data)
+fn void Adler32.update(&self, char[] data)
 {
-    uint a = this.a;
-    uint b = this.b;
-    foreach (char x : data)
-    {
-        a = (a + x) % ADLER_CONST;
-        b = (b + a) % ADLER_CONST;
-    }
-    *this = { a, b };
+	uint a = self.a;
+	uint b = self.b;
+	foreach (char x : data)
+	{
+		a = (a + x) % ADLER_CONST;
+		b = (b + a) % ADLER_CONST;
+	}
+	*self = { a, b };
 }

-fn uint Adler32.final(Adler32* this)
+fn uint Adler32.final(&self)
 {
-    return (this.b << 16) | this.a;
+	return (self.b << 16) | self.a;
 }

 fn uint encode(char[] data)
 {
-    uint a = 1;
-    uint b = 0;
-    foreach (char x : data)
-    {
-        a = (a + x) % ADLER_CONST;
-        b = (b + a) % ADLER_CONST;
-    }
-    return (b << 16) | a;
+	uint a = 1;
+	uint b = 0;
+	foreach (char x : data)
+	{
+		a = (a + x) % ADLER_CONST;
+		b = (b + a) % ADLER_CONST;
+	}
+	return (b << 16) | a;
 }
--- a/lib/std/hash/crc32.c3
+++ b/lib/std/hash/crc32.c3
@@ -5,41 +5,41 @@ module std::hash::crc32;

 struct Crc32
 {
-    uint result;
+	uint result;
 }

-fn void Crc32.init(Crc32* this, uint seed = 0)
+fn void Crc32.init(&self, uint seed = 0)
 {
-    this.result = ~seed;
+	self.result = ~seed;
 }

-fn void Crc32.updatec(Crc32* this, char c)
+fn void Crc32.updatec(&self, char c)
 {
-    this.result = (this.result >> 8) ^ CRC32_TABLE[(this.result ^ c) & 0xFF];
+	self.result = (self.result >> 8) ^ CRC32_TABLE[(self.result ^ c) & 0xFF];
 }

-fn void Crc32.update(Crc32* this, char[] data)
+fn void Crc32.update(&self, char[] data)
 {
-    uint result = this.result;
-    foreach (char x : data)
-    {
-        result = (result >> 8) ^ CRC32_TABLE[(result ^ x) & 0xFF];
-    }
-    this.result = result;
+	uint result = self.result;
+	foreach (char x : data)
+	{
+		result = (result >> 8) ^ CRC32_TABLE[(result ^ x) & 0xFF];
+	}
+	self.result = result;
 }

-fn uint Crc32.final(Crc32* this)
+fn uint Crc32.final(&self)
 {
-    return ~this.result;
+	return ~self.result;
 }

 fn uint encode(char[] data)
 {
-    uint result = ~(uint)(0);
-    foreach (char x : data)
-    {
-        result = (result >> 8) ^ CRC32_TABLE[(result ^ x) & 0xFF];
-    }
+	uint result = ~(uint)(0);
+	foreach (char x : data)
+	{
+		result = (result >> 8) ^ CRC32_TABLE[(result ^ x) & 0xFF];
+	}
 	return ~result;
 }

--- a/lib/std/hash/crc64.c3
+++ b/lib/std/hash/crc64.c3
@@ -5,107 +5,107 @@ module std::hash::crc64;

 struct Crc64
 {
-    ulong result;
+	ulong result;
 }

-fn void Crc64.init(Crc64* this, uint seed = 0)
+fn void Crc64.init(&self, uint seed = 0)
 {
-    this.result = seed;
+	self.result = seed;
 }

-fn void Crc64.updatec(Crc64* this, char c)
+fn void Crc64.updatec(&self, char c)
 {
-    this.result = (this.result << 8) ^ CRC64_TABLE[(char)((this.result >> 56) ^ c)];
+	self.result = (self.result << 8) ^ CRC64_TABLE[(char)((self.result >> 56) ^ c)];
 }

-fn void Crc64.update(Crc64* this, char[] data)
+fn void Crc64.update(&self, char[] data)
 {
-    ulong result = this.result;
-    foreach (char x : data)
-    {
-        result = (result << 8) ^ CRC64_TABLE[(char)((result >> 56) ^ x)];
-    }
-    this.result = result;
+	ulong result = self.result;
+	foreach (char x : data)
+	{
+		result = (result << 8) ^ CRC64_TABLE[(char)((result >> 56) ^ x)];
+	}
+	self.result = result;
 }

-fn ulong Crc64.final(Crc64* this)
+fn ulong Crc64.final(&self)
 {
-    return this.result;
+	return self.result;
 }

 fn ulong encode(char[] data)
 {
-    ulong result = (ulong)(0);
-    foreach (char x : data)
-    {
-        result = (result << 8) ^ CRC64_TABLE[(char)((result >> 56) ^ x)];
-    }
+	ulong result = (ulong)(0);
+	foreach (char x : data)
+	{
+		result = (result << 8) ^ CRC64_TABLE[(char)((result >> 56) ^ x)];
+	}
 	return result;
 }

 const ulong[256] CRC64_TABLE @private = {
-    0x0000000000000000, 0x42f0e1eba9ea3693, 0x85e1c3d753d46d26, 0xc711223cfa3e5bb5,
-   	0x493366450e42ecdf, 0x0bc387aea7a8da4c, 0xccd2a5925d9681f9, 0x8e224479f47cb76a,
-   	0x9266cc8a1c85d9be, 0xd0962d61b56fef2d, 0x17870f5d4f51b498, 0x5577eeb6e6bb820b,
-   	0xdb55aacf12c73561, 0x99a54b24bb2d03f2, 0x5eb4691841135847, 0x1c4488f3e8f96ed4,
-   	0x663d78ff90e185ef, 0x24cd9914390bb37c, 0xe3dcbb28c335e8c9, 0xa12c5ac36adfde5a,
-   	0x2f0e1eba9ea36930, 0x6dfeff5137495fa3, 0xaaefdd6dcd770416, 0xe81f3c86649d3285,
-   	0xf45bb4758c645c51, 0xb6ab559e258e6ac2, 0x71ba77a2dfb03177, 0x334a9649765a07e4,
-   	0xbd68d2308226b08e, 0xff9833db2bcc861d, 0x388911e7d1f2dda8, 0x7a79f00c7818eb3b,
-   	0xcc7af1ff21c30bde, 0x8e8a101488293d4d, 0x499b3228721766f8, 0x0b6bd3c3dbfd506b,
-   	0x854997ba2f81e701, 0xc7b97651866bd192, 0x00a8546d7c558a27, 0x4258b586d5bfbcb4,
-   	0x5e1c3d753d46d260, 0x1cecdc9e94ace4f3, 0xdbfdfea26e92bf46, 0x990d1f49c77889d5,
-   	0x172f5b3033043ebf, 0x55dfbadb9aee082c, 0x92ce98e760d05399, 0xd03e790cc93a650a,
-   	0xaa478900b1228e31, 0xe8b768eb18c8b8a2, 0x2fa64ad7e2f6e317, 0x6d56ab3c4b1cd584,
-   	0xe374ef45bf6062ee, 0xa1840eae168a547d, 0x66952c92ecb40fc8, 0x2465cd79455e395b,
-   	0x3821458aada7578f, 0x7ad1a461044d611c, 0xbdc0865dfe733aa9, 0xff3067b657990c3a,
-   	0x711223cfa3e5bb50, 0x33e2c2240a0f8dc3, 0xf4f3e018f031d676, 0xb60301f359dbe0e5,
-   	0xda050215ea6c212f, 0x98f5e3fe438617bc, 0x5fe4c1c2b9b84c09, 0x1d14202910527a9a,
-   	0x93366450e42ecdf0, 0xd1c685bb4dc4fb63, 0x16d7a787b7faa0d6, 0x5427466c1e109645,
-   	0x4863ce9ff6e9f891, 0x0a932f745f03ce02, 0xcd820d48a53d95b7, 0x8f72eca30cd7a324,
-   	0x0150a8daf8ab144e, 0x43a04931514122dd, 0x84b16b0dab7f7968, 0xc6418ae602954ffb,
-   	0xbc387aea7a8da4c0, 0xfec89b01d3679253, 0x39d9b93d2959c9e6, 0x7b2958d680b3ff75,
-   	0xf50b1caf74cf481f, 0xb7fbfd44dd257e8c, 0x70eadf78271b2539, 0x321a3e938ef113aa,
-   	0x2e5eb66066087d7e, 0x6cae578bcfe24bed, 0xabbf75b735dc1058, 0xe94f945c9c3626cb,
-   	0x676dd025684a91a1, 0x259d31cec1a0a732, 0xe28c13f23b9efc87, 0xa07cf2199274ca14,
-   	0x167ff3eacbaf2af1, 0x548f120162451c62, 0x939e303d987b47d7, 0xd16ed1d631917144,
-   	0x5f4c95afc5edc62e, 0x1dbc74446c07f0bd, 0xdaad56789639ab08, 0x985db7933fd39d9b,
-   	0x84193f60d72af34f, 0xc6e9de8b7ec0c5dc, 0x01f8fcb784fe9e69, 0x43081d5c2d14a8fa,
-   	0xcd2a5925d9681f90, 0x8fdab8ce70822903, 0x48cb9af28abc72b6, 0x0a3b7b1923564425,
-   	0x70428b155b4eaf1e, 0x32b26afef2a4998d, 0xf5a348c2089ac238, 0xb753a929a170f4ab,
-   	0x3971ed50550c43c1, 0x7b810cbbfce67552, 0xbc902e8706d82ee7, 0xfe60cf6caf321874,
-   	0xe224479f47cb76a0, 0xa0d4a674ee214033, 0x67c58448141f1b86, 0x253565a3bdf52d15,
-   	0xab1721da49899a7f, 0xe9e7c031e063acec, 0x2ef6e20d1a5df759, 0x6c0603e6b3b7c1ca,
-   	0xf6fae5c07d3274cd, 0xb40a042bd4d8425e, 0x731b26172ee619eb, 0x31ebc7fc870c2f78,
-   	0xbfc9838573709812, 0xfd39626eda9aae81, 0x3a28405220a4f534, 0x78d8a1b9894ec3a7,
-   	0x649c294a61b7ad73, 0x266cc8a1c85d9be0, 0xe17dea9d3263c055, 0xa38d0b769b89f6c6,
-   	0x2daf4f0f6ff541ac, 0x6f5faee4c61f773f, 0xa84e8cd83c212c8a, 0xeabe6d3395cb1a19,
-   	0x90c79d3fedd3f122, 0xd2377cd44439c7b1, 0x15265ee8be079c04, 0x57d6bf0317edaa97,
-   	0xd9f4fb7ae3911dfd, 0x9b041a914a7b2b6e, 0x5c1538adb04570db, 0x1ee5d94619af4648,
-   	0x02a151b5f156289c, 0x4051b05e58bc1e0f, 0x87409262a28245ba, 0xc5b073890b687329,
-   	0x4b9237f0ff14c443, 0x0962d61b56fef2d0, 0xce73f427acc0a965, 0x8c8315cc052a9ff6,
-   	0x3a80143f5cf17f13, 0x7870f5d4f51b4980, 0xbf61d7e80f251235, 0xfd913603a6cf24a6,
-   	0x73b3727a52b393cc, 0x31439391fb59a55f, 0xf652b1ad0167feea, 0xb4a25046a88dc879,
-   	0xa8e6d8b54074a6ad, 0xea16395ee99e903e, 0x2d071b6213a0cb8b, 0x6ff7fa89ba4afd18,
-   	0xe1d5bef04e364a72, 0xa3255f1be7dc7ce1, 0x64347d271de22754, 0x26c49cccb40811c7,
-   	0x5cbd6cc0cc10fafc, 0x1e4d8d2b65facc6f, 0xd95caf179fc497da, 0x9bac4efc362ea149,
-   	0x158e0a85c2521623, 0x577eeb6e6bb820b0, 0x906fc95291867b05, 0xd29f28b9386c4d96,
-   	0xcedba04ad0952342, 0x8c2b41a1797f15d1, 0x4b3a639d83414e64, 0x09ca82762aab78f7,
-   	0x87e8c60fded7cf9d, 0xc51827e4773df90e, 0x020905d88d03a2bb, 0x40f9e43324e99428,
-   	0x2cffe7d5975e55e2, 0x6e0f063e3eb46371, 0xa91e2402c48a38c4, 0xebeec5e96d600e57,
-   	0x65cc8190991cb93d, 0x273c607b30f68fae, 0xe02d4247cac8d41b, 0xa2dda3ac6322e288,
-   	0xbe992b5f8bdb8c5c, 0xfc69cab42231bacf, 0x3b78e888d80fe17a, 0x7988096371e5d7e9,
-   	0xf7aa4d1a85996083, 0xb55aacf12c735610, 0x724b8ecdd64d0da5, 0x30bb6f267fa73b36,
-   	0x4ac29f2a07bfd00d, 0x08327ec1ae55e69e, 0xcf235cfd546bbd2b, 0x8dd3bd16fd818bb8,
-   	0x03f1f96f09fd3cd2, 0x41011884a0170a41, 0x86103ab85a2951f4, 0xc4e0db53f3c36767,
-   	0xd8a453a01b3a09b3, 0x9a54b24bb2d03f20, 0x5d45907748ee6495, 0x1fb5719ce1045206,
-   	0x919735e51578e56c, 0xd367d40ebc92d3ff, 0x1476f63246ac884a, 0x568617d9ef46bed9,
-   	0xe085162ab69d5e3c, 0xa275f7c11f7768af, 0x6564d5fde549331a, 0x279434164ca30589,
-   	0xa9b6706fb8dfb2e3, 0xeb46918411358470, 0x2c57b3b8eb0bdfc5, 0x6ea7525342e1e956,
-   	0x72e3daa0aa188782, 0x30133b4b03f2b111, 0xf7021977f9cceaa4, 0xb5f2f89c5026dc37,
-   	0x3bd0bce5a45a6b5d, 0x79205d0e0db05dce, 0xbe317f32f78e067b, 0xfcc19ed95e6430e8,
-   	0x86b86ed5267cdbd3, 0xc4488f3e8f96ed40, 0x0359ad0275a8b6f5, 0x41a94ce9dc428066,
-   	0xcf8b0890283e370c, 0x8d7be97b81d4019f, 0x4a6acb477bea5a2a, 0x089a2aacd2006cb9,
-   	0x14dea25f3af9026d, 0x562e43b4931334fe, 0x913f6188692d6f4b, 0xd3cf8063c0c759d8,
-   	0x5dedc41a34bbeeb2, 0x1f1d25f19d51d821, 0xd80c07cd676f8394, 0x9afce626ce85b507,
+	0x0000000000000000, 0x42f0e1eba9ea3693, 0x85e1c3d753d46d26, 0xc711223cfa3e5bb5,
+	0x493366450e42ecdf, 0x0bc387aea7a8da4c, 0xccd2a5925d9681f9, 0x8e224479f47cb76a,
+	0x9266cc8a1c85d9be, 0xd0962d61b56fef2d, 0x17870f5d4f51b498, 0x5577eeb6e6bb820b,
+	0xdb55aacf12c73561, 0x99a54b24bb2d03f2, 0x5eb4691841135847, 0x1c4488f3e8f96ed4,
+	0x663d78ff90e185ef, 0x24cd9914390bb37c, 0xe3dcbb28c335e8c9, 0xa12c5ac36adfde5a,
+	0x2f0e1eba9ea36930, 0x6dfeff5137495fa3, 0xaaefdd6dcd770416, 0xe81f3c86649d3285,
+	0xf45bb4758c645c51, 0xb6ab559e258e6ac2, 0x71ba77a2dfb03177, 0x334a9649765a07e4,
+	0xbd68d2308226b08e, 0xff9833db2bcc861d, 0x388911e7d1f2dda8, 0x7a79f00c7818eb3b,
+	0xcc7af1ff21c30bde, 0x8e8a101488293d4d, 0x499b3228721766f8, 0x0b6bd3c3dbfd506b,
+	0x854997ba2f81e701, 0xc7b97651866bd192, 0x00a8546d7c558a27, 0x4258b586d5bfbcb4,
+	0x5e1c3d753d46d260, 0x1cecdc9e94ace4f3, 0xdbfdfea26e92bf46, 0x990d1f49c77889d5,
+	0x172f5b3033043ebf, 0x55dfbadb9aee082c, 0x92ce98e760d05399, 0xd03e790cc93a650a,
+	0xaa478900b1228e31, 0xe8b768eb18c8b8a2, 0x2fa64ad7e2f6e317, 0x6d56ab3c4b1cd584,
+	0xe374ef45bf6062ee, 0xa1840eae168a547d, 0x66952c92ecb40fc8, 0x2465cd79455e395b,
+	0x3821458aada7578f, 0x7ad1a461044d611c, 0xbdc0865dfe733aa9, 0xff3067b657990c3a,
+	0x711223cfa3e5bb50, 0x33e2c2240a0f8dc3, 0xf4f3e018f031d676, 0xb60301f359dbe0e5,
+	0xda050215ea6c212f, 0x98f5e3fe438617bc, 0x5fe4c1c2b9b84c09, 0x1d14202910527a9a,
+	0x93366450e42ecdf0, 0xd1c685bb4dc4fb63, 0x16d7a787b7faa0d6, 0x5427466c1e109645,
+	0x4863ce9ff6e9f891, 0x0a932f745f03ce02, 0xcd820d48a53d95b7, 0x8f72eca30cd7a324,
+	0x0150a8daf8ab144e, 0x43a04931514122dd, 0x84b16b0dab7f7968, 0xc6418ae602954ffb,
+	0xbc387aea7a8da4c0, 0xfec89b01d3679253, 0x39d9b93d2959c9e6, 0x7b2958d680b3ff75,
+	0xf50b1caf74cf481f, 0xb7fbfd44dd257e8c, 0x70eadf78271b2539, 0x321a3e938ef113aa,
+	0x2e5eb66066087d7e, 0x6cae578bcfe24bed, 0xabbf75b735dc1058, 0xe94f945c9c3626cb,
+	0x676dd025684a91a1, 0x259d31cec1a0a732, 0xe28c13f23b9efc87, 0xa07cf2199274ca14,
+	0x167ff3eacbaf2af1, 0x548f120162451c62, 0x939e303d987b47d7, 0xd16ed1d631917144,
+	0x5f4c95afc5edc62e, 0x1dbc74446c07f0bd, 0xdaad56789639ab08, 0x985db7933fd39d9b,
+	0x84193f60d72af34f, 0xc6e9de8b7ec0c5dc, 0x01f8fcb784fe9e69, 0x43081d5c2d14a8fa,
+	0xcd2a5925d9681f90, 0x8fdab8ce70822903, 0x48cb9af28abc72b6, 0x0a3b7b1923564425,
+	0x70428b155b4eaf1e, 0x32b26afef2a4998d, 0xf5a348c2089ac238, 0xb753a929a170f4ab,
+	0x3971ed50550c43c1, 0x7b810cbbfce67552, 0xbc902e8706d82ee7, 0xfe60cf6caf321874,
+	0xe224479f47cb76a0, 0xa0d4a674ee214033, 0x67c58448141f1b86, 0x253565a3bdf52d15,
+	0xab1721da49899a7f, 0xe9e7c031e063acec, 0x2ef6e20d1a5df759, 0x6c0603e6b3b7c1ca,
+	0xf6fae5c07d3274cd, 0xb40a042bd4d8425e, 0x731b26172ee619eb, 0x31ebc7fc870c2f78,
+	0xbfc9838573709812, 0xfd39626eda9aae81, 0x3a28405220a4f534, 0x78d8a1b9894ec3a7,
+	0x649c294a61b7ad73, 0x266cc8a1c85d9be0, 0xe17dea9d3263c055, 0xa38d0b769b89f6c6,
+	0x2daf4f0f6ff541ac, 0x6f5faee4c61f773f, 0xa84e8cd83c212c8a, 0xeabe6d3395cb1a19,
+	0x90c79d3fedd3f122, 0xd2377cd44439c7b1, 0x15265ee8be079c04, 0x57d6bf0317edaa97,
+	0xd9f4fb7ae3911dfd, 0x9b041a914a7b2b6e, 0x5c1538adb04570db, 0x1ee5d94619af4648,
+	0x02a151b5f156289c, 0x4051b05e58bc1e0f, 0x87409262a28245ba, 0xc5b073890b687329,
+	0x4b9237f0ff14c443, 0x0962d61b56fef2d0, 0xce73f427acc0a965, 0x8c8315cc052a9ff6,
+	0x3a80143f5cf17f13, 0x7870f5d4f51b4980, 0xbf61d7e80f251235, 0xfd913603a6cf24a6,
+	0x73b3727a52b393cc, 0x31439391fb59a55f, 0xf652b1ad0167feea, 0xb4a25046a88dc879,
+	0xa8e6d8b54074a6ad, 0xea16395ee99e903e, 0x2d071b6213a0cb8b, 0x6ff7fa89ba4afd18,
+	0xe1d5bef04e364a72, 0xa3255f1be7dc7ce1, 0x64347d271de22754, 0x26c49cccb40811c7,
+	0x5cbd6cc0cc10fafc, 0x1e4d8d2b65facc6f, 0xd95caf179fc497da, 0x9bac4efc362ea149,
+	0x158e0a85c2521623, 0x577eeb6e6bb820b0, 0x906fc95291867b05, 0xd29f28b9386c4d96,
+	0xcedba04ad0952342, 0x8c2b41a1797f15d1, 0x4b3a639d83414e64, 0x09ca82762aab78f7,
+	0x87e8c60fded7cf9d, 0xc51827e4773df90e, 0x020905d88d03a2bb, 0x40f9e43324e99428,
+	0x2cffe7d5975e55e2, 0x6e0f063e3eb46371, 0xa91e2402c48a38c4, 0xebeec5e96d600e57,
+	0x65cc8190991cb93d, 0x273c607b30f68fae, 0xe02d4247cac8d41b, 0xa2dda3ac6322e288,
+	0xbe992b5f8bdb8c5c, 0xfc69cab42231bacf, 0x3b78e888d80fe17a, 0x7988096371e5d7e9,
+	0xf7aa4d1a85996083, 0xb55aacf12c735610, 0x724b8ecdd64d0da5, 0x30bb6f267fa73b36,
+	0x4ac29f2a07bfd00d, 0x08327ec1ae55e69e, 0xcf235cfd546bbd2b, 0x8dd3bd16fd818bb8,
+	0x03f1f96f09fd3cd2, 0x41011884a0170a41, 0x86103ab85a2951f4, 0xc4e0db53f3c36767,
+	0xd8a453a01b3a09b3, 0x9a54b24bb2d03f20, 0x5d45907748ee6495, 0x1fb5719ce1045206,
+	0x919735e51578e56c, 0xd367d40ebc92d3ff, 0x1476f63246ac884a, 0x568617d9ef46bed9,
+	0xe085162ab69d5e3c, 0xa275f7c11f7768af, 0x6564d5fde549331a, 0x279434164ca30589,
+	0xa9b6706fb8dfb2e3, 0xeb46918411358470, 0x2c57b3b8eb0bdfc5, 0x6ea7525342e1e956,
+	0x72e3daa0aa188782, 0x30133b4b03f2b111, 0xf7021977f9cceaa4, 0xb5f2f89c5026dc37,
+	0x3bd0bce5a45a6b5d, 0x79205d0e0db05dce, 0xbe317f32f78e067b, 0xfcc19ed95e6430e8,
+	0x86b86ed5267cdbd3, 0xc4488f3e8f96ed40, 0x0359ad0275a8b6f5, 0x41a94ce9dc428066,
+	0xcf8b0890283e370c, 0x8d7be97b81d4019f, 0x4a6acb477bea5a2a, 0x089a2aacd2006cb9,
+	0x14dea25f3af9026d, 0x562e43b4931334fe, 0x913f6188692d6f4b, 0xd3cf8063c0c759d8,
+	0x5dedc41a34bbeeb2, 0x1f1d25f19d51d821, 0xd80c07cd676f8394, 0x9afce626ce85b507,
 };
--- a/lib/std/hash/fnv32a.c3
+++ b/lib/std/hash/fnv32a.c3
@@ -3,39 +3,39 @@
 // a copy of which can be found in the LICENSE_STDLIB file.
 module std::hash::fnv32a;

-typedef Fnv32a = distinct uint;
+distinct Fnv32a = uint;

 const FNV32A_START @private = 0x811c9dc5;
 const FNV32A_MUL @private = 0x01000193;

-macro void @update(uint &h, char x) @private => h = (h * FNV32A_MUL) ^ x;
+macro void @update(uint* &h, char x) @private => *h = (*h * FNV32A_MUL) ^ x;

-fn void Fnv32a.init(Fnv32a* this)
+fn void Fnv32a.init(&self)
 {
-    *this = FNV32A_START;
+	*self = FNV32A_START;
 }

-fn void Fnv32a.update(Fnv32a* this, char[] data)
+fn void Fnv32a.update(&self, char[] data)
 {
-	uint h = (uint)*this;
+	uint h = (uint)*self;
 	foreach (char x : data)
-    {
-        @update(h, x);
-    }
-    *this = (Fnv32a)h;
+	{
+		@update(h, x);
+	}
+	*self = (Fnv32a)h;
 }

-macro void Fnv32a.update_char(Fnv32a* this, char c)
+macro void Fnv32a.update_char(&self, char c)
 {
-	@update(*this, x);
+	@update(*self, x);
 }

 fn uint encode(char[] data)
 {
 	uint h = FNV32A_START;
 	foreach (char x : data)
-    {
+	{
 		@update(h, x);
-    }
-    return h;
+	}
+	return h;
 }
--- a/lib/std/hash/fnv64a.c3
+++ b/lib/std/hash/fnv64a.c3
@@ -0,0 +1,41 @@
+// Copyright (c) 2021 Christoffer Lerno. All rights reserved.
+// Use of this source code is governed by the MIT license
+// a copy of which can be found in the LICENSE_STDLIB file.
+module std::hash::fnv64a;
+
+distinct Fnv64a = ulong;
+
+const FNV64A_START @private = 0xcbf29ce484222325;
+const FNV64A_MUL @private = 0x00000100000001b3;
+
+macro void @update(ulong* &h, char x) @private => *h = (*h * FNV64A_MUL) ^ x;
+
+fn void Fnv64a.init(&self)
+{
+	*self = FNV64A_START;
+}
+
+fn void Fnv64a.update(&self, char[] data)
+{
+	ulong h = (ulong)*self;
+	foreach (char x : data)
+	{
+		@update(h, x);
+	}
+	*self = (Fnv64a)h;
+}
+
+macro void Fnv64a.update_char(&self, char c)
+{
+	@update(*self, x);
+}
+
+fn ulong encode(char[] data)
+{
+	ulong h = FNV64A_START;
+	foreach (char x : data)
+	{
+		@update(h, x);
+	}
+	return h;
+}
--- a/lib/std/hash/sha1.c3
+++ b/lib/std/hash/sha1.c3
@@ -14,70 +14,69 @@ struct Sha1
 	char[64] buffer;
 }

-fn void Sha1.init(Sha1* this)
+fn void Sha1.init(&self)
 {
-    // SHA1 initialization constants
-    *this = {
-        .state = {
-            0x67452301,
-            0xEFCDAB89,
-            0x98BADCFE,
-            0x10325476,
-            0xC3D2E1F0
-        }
+	// SHA1 initialization constants
+	*self = {
+		.state = {
+			0x67452301,
+			0xEFCDAB89,
+			0x98BADCFE,
+			0x10325476,
+			0xC3D2E1F0
+		}
 	};
 }

 /**
- * @param [&inout] this
 * @param [in] data
 * @require data.len <= uint.max
 **/
-fn void Sha1.update(Sha1* this, char[] data)
+fn void Sha1.update(&self, char[] data)
 {
-	uint j = this.count[0];
+	uint j = self.count[0];
 	uint len = data.len;
-	if ((this.count[0] += len << 3) < j) this.count[1]++;
-	this.count[1] += len >> 29;
+	if ((self.count[0] += len << 3) < j) self.count[1]++;
+	self.count[1] += len >> 29;
 	j = (j >> 3) & 63;
 	uint i;
 	if (j + len > 63)
 	{
 		i = 64 - j;
-		this.buffer[j..] = data[:i];
-		sha1_transform(&this.state, &this.buffer);
+		self.buffer[j..] = data[:i];
+		sha1_transform(&self.state, &self.buffer);
 		for (; i + 63 < len; i += 64)
 		{
-			sha1_transform(&this.state, &data[i]);
+			sha1_transform(&self.state, &data[i]);
 		}
 		j = 0;
 	}
-	this.buffer[j:len - i] = data[i..];
+	self.buffer[j:len - i] = data[i..];
 }


-fn char[20] Sha1.final(Sha1* this)
+fn char[20] Sha1.final(&self)
 {
 	char[8] finalcount;
 	for (uint i = 0; i < 8; i++)
 	{
-		finalcount[i] = (char)((this.count[(i >= 4 ? 0 : 1)] >> ((3 - (i & 3)) * 8)) & 0xFF);
+		finalcount[i] = (char)((self.count[(i >= 4 ? 0 : 1)] >> ((3 - (i & 3)) * 8)) & 0xFF);
 	}
-	this.update(char[] { 0o200 });
-	while ((this.count[0] & 504) != 448)
+	self.update(char[] { 0o200 });
+	while ((self.count[0] & 504) != 448)
 	{
-		this.update(char[] { 0 });
+		self.update(char[] { 0 });
 	}

-	this.update(&finalcount);
+	self.update(&finalcount);
 	char[20] digest;
 	for (uint i = 0; i < 20; i++)
 	{
-		digest[i] = (char)((this.state[i >> 2] >> ((3 - (i & 3)) * 8)) & 0xFF);
+		digest[i] = (char)((self.state[i >> 2] >> ((3 - (i & 3)) * 8)) & 0xFF);
 	}

 	// Clear mem
-	mem::clear(this, Sha1.sizeof);
+	mem::clear(self, Sha1.sizeof);
 	finalcount = {};
 	return digest;
 }
@@ -96,42 +95,47 @@ macro @blk(&block, i) @local

 macro @blk0(&block, i) @local
 {
-$if (env::BIG_ENDIAN)
-	return block.l[i];
-$else
-	return block.l[i] = (block.l[i].rotl(24) & 0xFF00FF00)
-        | (block.l[i].rotl(8) & 0x00FF00FF);
-$endif
+	$if env::BIG_ENDIAN:
+		return block.l[i];
+	$else
+		return block.l[i] = (block.l[i].rotl(24) & 0xFF00FF00)
+			| (block.l[i].rotl(8) & 0x00FF00FF);
+	$endif
 }

-macro @r0(&block, v, &w, x, y, &z, i) @local
+macro @r0(&block, v, &wref, x, y, &z, i) @local
 {
-	z += ((w & (x ^ y)) ^ y) + @blk0(block, i) + 0x5A827999 + v.rotl(5);
-	w = w.rotl(30);
+	var w = *wref;
+	*z += ((w & (x ^ y)) ^ y) + @blk0(*block, i) + 0x5A827999 + v.rotl(5);
+	*wref = w.rotl(30);
 }

-macro @r1(&block, v, &w, x, y, &z, i) @local
+macro @r1(&block, v, &wref, x, y, &z, i) @local
 {
-	z += ((w & (x ^ y)) ^ y) + @blk(block, i) + 0x5A827999 + v.rotl(5);
-	w = w.rotl(30);
+	var w = *wref;
+	*z += ((w & (x ^ y)) ^ y) + @blk(*block, i) + 0x5A827999 + v.rotl(5);
+	*wref = w.rotl(30);
 }

-macro @r2(&block, v, &w, x, y, &z, i) @local
+macro @r2(&block, v, &wref, x, y, &z, i) @local
 {
-	z += (w ^ x ^ y) + @blk(block, i) + 0x6ED9EBA1 + v.rotl(5);
-	w = w.rotl(30);
+	var w = *wref;
+	*z += (w ^ x ^ y) + @blk(*block, i) + 0x6ED9EBA1 + v.rotl(5);
+	*wref = w.rotl(30);
 }

-macro @r3(&block, v, &w, x, y, &z, i) @local
+macro @r3(&block, v, &wref, x, y, &z, i) @local
 {
-	z += (((w | x) &y) | (w & x)) + @blk(block, i) + 0x8F1BBCDC + v.rotl(5);
-	w = w.rotl(30);
+	var w = *wref;
+	*z += (((w | x) & y) | (w & x)) + @blk(*block, i) + 0x8F1BBCDC + v.rotl(5);
+	*wref = w.rotl(30);
 }

-macro @r4(&block, v, &w, x, y, &z, i) @local
+macro @r4(&block, v, &wref, x, y, &z, i) @local
 {
-	z += (w ^ x ^ y) + @blk(block, i) + 0xCA62C1D6 + v.rotl(5);
-	w = w.rotl(30);
+	var w = *wref;
+	*z += (w ^ x ^ y) + @blk(*block, i) + 0xCA62C1D6 + v.rotl(5);
+	*wref = w.rotl(30);
 }

 /**
--- a/lib/std/io/bits.c3
+++ b/lib/std/io/bits.c3
@@ -0,0 +1,85 @@
+module std::io;
+
+struct BitReader
+{
+	InStream* reader;
+	uint bits;
+	uint len;
+}
+
+fn void BitReader.init(&self, InStream* byte_reader)
+{
+	*self = { .reader = byte_reader };
+}
+
+fn void BitReader.clear(&self) @inline
+{
+	self.len = 0;
+}
+
+/**
+ * @require nbits <= 8
+ * @require self.len + nbits <= uint.sizeof * 8
+ **/
+fn char! BitReader.read_bits(&self, uint nbits)
+{
+	uint bits = self.bits;
+	if (self.len < nbits)
+	{
+		// New bits are pushed right.
+		char c = self.reader.read_byte()!;
+		bits <<= 8;
+		bits |= c;
+		self.bits = bits;
+		self.len += 8;
+	}
+	self.len -= nbits;
+	uint mask = (1 << nbits) - 1;
+	return (char)((bits >> self.len) & mask);
+}
+
+struct BitWriter
+{
+	OutStream* writer;
+	uint bits;
+	uint len;
+}
+
+fn void BitWriter.init(&self, OutStream* byte_writer)
+{
+	*self = { .writer = byte_writer };
+}
+
+fn void! BitWriter.flush(&self)
+{
+	if (self.len == 0) return;
+	uint bits = self.bits << (32 - self.len);
+	uint n = (self.len + 7) / 8;
+	char[4] buffer;
+	bitorder::write(bits, &buffer, UIntBE);
+	io::write_all(self.writer, buffer[:n])!;
+	self.len = 0;
+}
+
+/**
+ * @require nbits <= 8
+ **/
+fn void! BitWriter.write_bits(&self, uint bits, uint nbits)
+{
+	if (nbits == 0) return;
+	uint n = self.len + nbits;
+	uint to_write = n / 8;
+	uint left = n % 8;
+	if (to_write > 0)
+	{
+		ulong lbits;
+		if (self.len > 0) lbits = (ulong)self.bits << (64 - self.len);
+		lbits |= (ulong)(bits >> left) << (64 - (n - left));
+		char[8] buffer;
+		bitorder::write(lbits, &buffer, ULongBE);
+		io::write_all(self.writer, buffer[:to_write])!;
+	}
+	self.bits <<= left;
+	self.bits |= bits & ((1 << left) - 1);
+	self.len = left;
+}
--- a/lib/std/io/dir.c3
+++ b/lib/std/io/dir.c3
@@ -1,3 +0,0 @@
-module std::io::dir;
-import std::io::os;
-
--- a/lib/std/io/file.c3
+++ b/lib/std/io/file.c3
@@ -0,0 +1,191 @@
+module std::io;
+import libc;
+
+struct File (InStream, OutStream)
+{
+	CFile file;
+}
+
+module std::io::file;
+import libc;
+
+fn File! open(String filename, String mode)
+{
+	return from_handle(os::native_fopen(filename, mode));
+}
+
+fn File! open_path(Path path, String mode)
+{
+	return from_handle(os::native_fopen(path.str_view(), mode));
+}
+
+fn File from_handle(CFile file)
+{
+	return { .file = file };
+}
+
+fn bool is_file(String path)
+{
+	return os::native_is_file(path);
+}
+
+fn usz! get_size(String path)
+{
+	return os::native_file_size(path);
+}
+
+fn void! delete(String filename) => os::native_remove(filename) @inline;
+
+
+/**
+ * @require self.file != null
+ **/
+fn void! File.reopen(&self, String filename, String mode)
+{
+	self.file = os::native_freopen(self.file, filename, mode)!;
+}
+
+/**
+ * @require self.file != null
+ **/
+fn usz! File.seek(&self, isz offset, Seek seek_mode = Seek.SET) @dynamic
+{
+	os::native_fseek(self.file, offset, seek_mode)!;
+	return os::native_ftell(self.file);
+}
+
+
+/*
+Implement later
+/**
+ * @require self.file == null
+ **/
+fn void! File.memopen(File* file, char[] data, String mode)
+{
+	@pool()
+	{
+		file.file = libc::memopen(data.ptr, data.len, mode.zstr_tcopy(), file.file);
+		// TODO errors
+	};
+}
+*/
+
+
+/**
+ * @require self.file != null
+ */
+fn void! File.write_byte(&self, char c) @dynamic
+{
+	if (!libc::fputc(c, self.file)) return IoError.EOF?;
+}
+
+/**
+ * @param [&inout] self
+ */
+fn void! File.close(&self) @inline @dynamic
+{
+	if (self.file && libc::fclose(self.file))
+	{
+		switch (libc::errno())
+		{
+			case errno::ECONNRESET:
+			case errno::EBADF: return IoError.FILE_NOT_VALID?;
+			case errno::EINTR: return IoError.INTERRUPTED?;
+			case errno::EDQUOT:
+			case errno::EFAULT:
+			case errno::EAGAIN:
+			case errno::EFBIG:
+			case errno::ENETDOWN:
+			case errno::ENETUNREACH:
+			case errno::ENOSPC:
+			case errno::EIO: return IoError.INCOMPLETE_WRITE?;
+			default: return IoError.UNKNOWN_ERROR?;
+		}
+	}
+	self.file = null;
+}
+
+/**
+ * @require self.file
+ */
+fn bool File.eof(&self) @inline
+{
+	return libc::feof(self.file) != 0;
+}
+
+/**
+ * @param [in] buffer
+ */
+fn usz! File.read(&self, char[] buffer) @dynamic
+{
+	return os::native_fread(self.file, buffer);
+}
+
+/**
+ * @param [out] buffer
+ * @require self.file `File must be initialized`
+ */
+fn usz! File.write(&self, char[] buffer) @dynamic
+{
+	return os::native_fwrite(self.file, buffer);
+}
+
+
+fn char! File.read_byte(&self) @dynamic
+{
+	int c = libc::fgetc(self.file);
+	if (c == -1) return IoError.EOF?;
+	return (char)c;
+}
+
+/**
+ * Load up to buffer.len characters. Returns IoError.OVERFLOW if the file is longer
+ * than the buffer.
+ *
+ * @param filename "The path to the file to read"
+ * @param [in] buffer "The buffer to read to"
+ **/
+fn char[]! load_buffer(String filename, char[] buffer)
+{
+	File file = open(filename, "rb")!;
+	defer (void)file.close();
+	usz len = file.seek(0, END)!;
+	if (len > buffer.len) return IoError.OVERFLOW?;
+	file.seek(0, SET)!;
+	usz read = 0;
+	while (read < len)
+	{
+		read += file.read(buffer[read:len - read])!;
+	}
+	return buffer[:len];
+
+}
+
+fn char[]! load_new(String filename, Allocator* allocator = mem::heap())
+{
+	File file = open(filename, "rb")!;
+	defer (void)file.close();
+	usz len = file.seek(0, END)!;
+	file.seek(0, SET)!;
+	char* data = allocator.alloc_checked(len)!;
+	defer catch allocator.free(data);
+	usz read = 0;
+	while (read < len)
+	{
+		read += file.read(data[read:len - read])!;
+	}
+	return data[:len];
+}
+
+fn char[]! load_temp(String filename)
+{
+	return load_new(filename, mem::temp());
+}
+
+/**
+ * @require self.file `File must be initialized`
+ */
+fn void! File.flush(&self) @dynamic
+{
+	libc::fflush(self.file);
+}
--- a/lib/std/io/formatter.c3
+++ b/lib/std/io/formatter.c3
@@ -0,0 +1,461 @@
+module std::io;
+import std::collections::map;
+import libc;
+
+const int PRINTF_NTOA_BUFFER_SIZE = 256;
+
+interface Printable
+{
+	fn String to_new_string(Allocator *allocator) @optional;
+	fn usz! to_format(Formatter* formatter) @optional;
+}
+
+fault PrintFault
+{
+	BUFFER_EXCEEDED,
+	INTERNAL_BUFFER_EXCEEDED,
+	INVALID_FORMAT_STRING,
+	MISSING_ARG,
+	INVALID_ARGUMENT_TYPE,
+}
+
+fault FormattingFault
+{
+	UNTERMINATED_FORMAT,
+	MISSING_ARG,
+	INVALID_WIDTH_ARG,
+	INVALID_FORMAT_TYPE,
+}
+
+def OutputFn = fn void!(void* buffer, char c);
+def FloatType = double;
+
+
+
+fn usz! Formatter.printf(&self, String format, args...)
+{
+	return self.vprintf(format, args) @inline;
+}
+
+struct Formatter
+{
+	void *data;
+	OutputFn out_fn;
+	struct
+	{
+		PrintFlags flags;
+		uint width;
+		uint prec;
+		usz idx;
+	}
+}
+
+bitstruct PrintFlags : uint
+{
+	bool zeropad;
+	bool left;
+	bool plus;
+	bool space;
+	bool hash;
+	bool uppercase;
+	bool precision;
+}
+
+fn void Formatter.init(&self, OutputFn out_fn, void* data = null)
+{
+	*self = { .data = data, .out_fn = out_fn};
+}
+
+fn usz! Formatter.out(&self, char c) @private
+{
+	self.out_fn(self.data, c)!;
+	return 1;
+}
+
+fn usz! Formatter.print_with_function(&self, Printable* arg)
+{
+	if (&arg.to_format)
+	{
+		PrintFlags old = self.flags;
+		uint old_width = self.width;
+		uint old_prec = self.prec;
+		defer
+		{
+			self.flags = old;
+			self.width = old_width;
+			self.prec = old_prec;
+		}
+		return arg.to_format(self);
+	}
+	if (&arg.to_new_string)
+	{
+		PrintFlags old = self.flags;
+		uint old_width = self.width;
+		uint old_prec = self.prec;
+		defer
+		{
+			self.flags = old;
+			self.width = old_width;
+			self.prec = old_prec;
+		}
+		@pool()
+		{
+			return self.out_substr(arg.to_new_string(mem::temp()));
+		};
+	}
+	return SearchResult.MISSING?;
+}
+
+
+fn usz! Formatter.out_str(&self, any* arg) @private
+{
+	switch (arg.type.kindof)
+	{
+		case TYPEID:
+			return self.out_substr("typeid");
+		case VOID:
+			return self.out_substr("void");
+		case ANYFAULT:
+		case FAULT:
+			return self.out_substr((*(anyfault*)arg.ptr).nameof);
+		case ANY:
+			return self.out_str(*(any**)arg);
+		case OPTIONAL:
+			unreachable();
+		case SIGNED_INT:
+		case UNSIGNED_INT:
+			PrintFlags flags = self.flags;
+			uint width = self.width;
+			defer
+			{
+				self.flags = flags;
+				self.width = width;
+			}
+			self.flags = {};
+			self.width = 0;
+			return self.ntoa_any(arg, 10);
+		case FLOAT:
+			PrintFlags flags = self.flags;
+			uint width = self.width;
+			defer
+			{
+				self.flags = flags;
+				self.width = width;
+			}
+			self.flags = {};
+			self.width = 0;
+			return self.ftoa(float_from_any(arg)!!);
+		case BOOL:
+			return self.out_substr(*(bool*)arg.ptr ? "true" : "false");
+		default:
+	}
+	usz! n = self.print_with_function((Printable*)arg);
+	if (catch err = n)
+	{
+		case SearchResult.MISSING:
+			break;
+		default:
+			return err?;
+	}
+	else
+	{
+		return n;
+	}
+	switch (arg.type.kindof)
+	{
+		case ENUM:
+			usz i = types::any_to_int(arg, usz)!!;
+			assert(i < arg.type.names.len, "Illegal enum value found, numerical value was %d.", i);
+			return self.out_substr(arg.type.names[i]);
+		case STRUCT:
+			return self.out_substr("<struct>");
+		case UNION:
+			return self.out_substr("<union>");
+		case BITSTRUCT:
+			return self.out_substr("<bitstruct>");
+		case FUNC:
+			return self.out_substr("<function>");
+		case DISTINCT:
+			if (arg.type == ZString.typeid)
+			{
+				return self.out_substr(((ZString*)arg).str_view());
+			}
+			if (arg.type == DString.typeid)
+			{
+				return self.out_substr(((DString*)arg).str_view());
+			}
+			return self.out_str(arg.as_inner());
+		case POINTER:
+			PrintFlags flags = self.flags;
+			uint width = self.width;
+			defer
+			{
+				self.flags = flags;
+				self.width = width;
+			}
+			self.flags = {};
+			self.width = 0;
+			return self.ntoa_any(arg, 16);
+		case ARRAY:
+			// this is SomeType[*] so grab the "SomeType"
+			PrintFlags flags = self.flags;
+			uint width = self.width;
+			defer
+			{
+				self.flags = flags;
+				self.width = width;
+			}
+			self.flags = {};
+			self.width = 0;
+			typeid inner = arg.type.inner;
+			usz size = inner.sizeof;
+			usz alen = arg.type.len;
+			// Pretend this is a String
+			void* ptr = (void*)arg.ptr;
+			usz len = self.out('[')!;
+			for (usz i = 0; i < alen; i++)
+			{
+				if (i != 0) len += self.out_substr(", ")!;
+				len += self.out_str(any_make(ptr, inner))!;
+				ptr += size;
+			}
+			len += self.out(']')!;
+			return len;
+		case VECTOR:
+			PrintFlags flags = self.flags;
+			uint width = self.width;
+			defer
+			{
+				self.flags = flags;
+				self.width = width;
+			}
+			self.flags = {};
+			self.width = 0;
+			// this is SomeType[*] so grab the "SomeType"
+			typeid inner = arg.type.inner;
+			usz size = inner.sizeof;
+			usz vlen = arg.type.len;
+			// Pretend this is a String
+			void* ptr = (void*)arg.ptr;
+			usz len = self.out_substr("[<")!;
+			for (usz i = 0; i < vlen; i++)
+			{
+				if (i != 0) len += self.out_substr(", ")!;
+				len += self.out_str(any_make(ptr, inner))!;
+				ptr += size;
+			}
+			len += self.out_substr(">]")!;
+			return len;
+		case SUBARRAY:
+			// this is SomeType[] so grab the "SomeType"
+			typeid inner = arg.type.inner;
+			if (inner == char.typeid)
+			{
+				return self.out_substr(*(String*)arg);
+			}
+			if (inner == void.typeid) inner = char.typeid;
+			PrintFlags flags = self.flags;
+			uint width = self.width;
+			defer
+			{
+				self.flags = flags;
+				self.width = width;
+			}
+			self.flags = {};
+			self.width = 0;
+			usz size = inner.sizeof;
+			// Pretend this is a String
+			String* temp = (void*)arg.ptr;
+			void* ptr = (void*)temp.ptr;
+			usz slen = temp.len;
+			usz len = self.out('[')!;
+			for (usz i = 0; i < slen; i++)
+			{
+				if (i != 0) len += self.out_substr(", ")!;
+				len += self.out_str(any_make(ptr, inner))!;
+				ptr += size;
+			}
+			len += self.out(']')!;
+			return len;
+		default:
+	}
+	return self.out_substr("Invalid type");
+}
+
+
+
+
+fn void! out_null_fn(void* data @unused, char c @unused) @private
+{
+}
+
+
+
+fn usz! Formatter.vprintf(&self, String format, any*[] anys)
+{
+	if (!self.out_fn)
+	{
+		// use null output function
+		self.out_fn = &out_null_fn;
+	}
+	usz total_len;
+	usz format_len = format.len;
+	usz variant_index = 0;
+	for (usz i = 0; i < format_len; i++)
+	{
+		// format specifier?  %[flags][width][.precision][length]
+		char c = format[i];
+		if (c != '%')
+		{
+			// no
+			total_len += self.out(c)!;
+			continue;
+		}
+		i++;
+		if (i >= format_len) return PrintFault.INVALID_FORMAT_STRING?;
+		c = format[i];
+		if (c == '%')
+		{
+			total_len += self.out(c)!;
+			continue;
+		}
+		// evaluate flags
+		self.flags = {};
+		while FLAG_EVAL: (true)
+		{
+			switch (c)
+			{
+				case '0': self.flags.zeropad = true;
+				case '-': self.flags.left = true;
+				case '+': self.flags.plus = true;
+				case ' ': self.flags.space = true;
+				case '#': self.flags.hash = true;
+				default: break FLAG_EVAL;
+			}
+			if (++i >= format_len) return PrintFault.INVALID_FORMAT_STRING?;
+			c = format[i];
+		}
+		// evaluate width field
+		int w = printf_parse_format_field(anys.ptr, anys.len, &variant_index, format.ptr, format.len, &i)!;
+		c = format[i];
+		if (w < 0)
+		{
+			self.flags.left = true;
+			w = -w;
+		}
+		self.width = w;
+		// evaluate precision field
+		self.prec = 0;
+		if (c == '.')
+		{
+			self.flags.precision = true;
+			if (++i >= format_len) return PrintFault.INVALID_FORMAT_STRING?;
+			int prec = printf_parse_format_field(anys.ptr, anys.len, &variant_index, format.ptr, format.len, &i)!;
+			self.prec = prec < 0 ? 0 : prec;
+			c = format[i];
+		}
+
+		// evaluate specifier
+		uint base = 0;
+		if (variant_index >= anys.len) return PrintFault.MISSING_ARG?;
+		any* current = anys[variant_index++];
+		switch (c)
+		{
+			case 'd':
+				base = 10;
+				self.flags.hash = false;
+			case 'X' :
+				self.flags.uppercase = true;
+				nextcase;
+			case 'x' :
+				base = 16;
+			case 'O':
+				self.flags.uppercase = true;
+				nextcase;
+			case 'o' :
+				base = 8;
+			case 'B':
+				self.flags.uppercase = true;
+				nextcase;
+			case 'b' :
+				base = 2;
+			case 'A':
+				self.flags.uppercase = true;
+				nextcase;
+			case 'a':
+				total_len += self.atoa(float_from_any(current)!!)!;
+				continue;
+			case 'F' :
+				self.flags.uppercase = true;
+				nextcase;
+			case 'f':
+				total_len += self.ftoa(float_from_any(current)!!)!;
+				continue;
+			case 'E':
+				self.flags.uppercase = true;
+				nextcase;
+			case 'e':
+				total_len += self.etoa(float_from_any(current)!!)!;
+				continue;
+			case 'G':
+				self.flags.uppercase = true;
+				nextcase;
+			case 'g':
+				total_len += self.gtoa(float_from_any(current)!!)!;
+				continue;
+			case 'c':
+				total_len += self.out_char(current)!;
+				continue;
+			case 's':
+				if (self.flags.left)
+				{
+					usz len = self.out_str(current)!;
+					total_len += len;
+					total_len += self.pad(' ', self.width, len)!;
+					continue;
+				}
+				OutputFn out_fn = self.out_fn;
+				self.out_fn = (OutputFn)&out_null_fn;
+				usz len = self.out_str(current)!;
+				self.out_fn = out_fn;
+				total_len += self.pad(' ', self.width, len)!;
+				total_len += self.out_str(current)!;
+				continue;
+			case 'p':
+				self.flags.zeropad = true;
+				self.flags.hash = true;
+				base = 16;
+			default:
+				return PrintFault.INVALID_FORMAT_STRING?;
+		}
+		if (base != 10)
+		{
+			self.flags.plus = false;
+			self.flags.space = false;
+		}
+		// ignore '0' flag when precision is given
+		if (self.flags.precision) self.flags.zeropad = false;
+
+		bool is_neg;
+		uint128 v = int_from_any(current, &is_neg)!!;
+
+		total_len += self.ntoa(v, is_neg, base)!;
+	}
+	// termination
+	//	out((char)0, buffer, idx < maxlen ? idx : maxlen - 1U, maxlen);
+
+	// return written chars without terminating \0
+	return total_len;
+}
+
+
+fn usz! Formatter.print(&self, String str)
+{
+	if (!self.out_fn)
+	{
+		// use null output function
+		self.out_fn = &out_null_fn;
+	}
+	foreach (c : str) self.out(c)!;
+	return self.idx;
+}
--- a/lib/std/io/io_formatter_private.c3
+++ b/lib/std/io/io_formatter_private.c3
@@ -3,30 +3,25 @@ module std::io;
 const char[16] XDIGITS_H = "0123456789ABCDEF";
 const char[16] XDIGITS_L = "0123456789abcdef";

-fn void! Formatter.left_adjust(Formatter* this, usz len) @local
+fn usz! Formatter.adjust(&self, usz len) @local
 {
-	if (!this.flags.left) return;
-	for (usz l = len; l < this.width; l++) this.out(' ')?;
+	if (!self.flags.left) return 0;
+	return self.pad(' ', self.width, len);
 }

-fn void! Formatter.right_adjust(Formatter* this, usz len) @local
+fn uint128! int_from_any(any* arg, bool *is_neg) @private
 {
-	if (this.flags.left) return;
-	for (usz l = len; l < this.width; l++) this.out(' ')?;
-}
-
-
-fn uint128! int_from_variant(variant arg, bool *is_neg) @private
-{
-	*is_neg = false;
-	if (arg.type.kindof == TypeKind.POINTER)
+	switch (arg.type.kindof)
 	{
-		return (uint128)(uptr)*(void**)arg.ptr;
+		case TypeKind.POINTER:
+			*is_neg = false;
+			return (uint128)(uptr)*(void**)arg.ptr;
+		case TypeKind.DISTINCT:
+		case TypeKind.ENUM:
+			return int_from_any(arg.as_inner(), is_neg);
+		default:
 	}
-	if (arg.type.kindof == TypeKind.DISTINCT)
-    {
-    	return int_from_variant(variant { arg.ptr, arg.type.inner }, is_neg);
-    }
+	*is_neg = false;
 	switch (arg)
 	{
 		case bool:
@@ -44,8 +39,8 @@ fn uint128! int_from_variant(variant arg, bool *is_neg) @private
 			long val = *arg;
 			return (*is_neg = val < 0) ? (~(uint128)val) + 1 : (uint128)val;
 		case int128:
-            int128 val = *arg;
-            return (*is_neg = val < 0) ? (~(uint128)val) + 1 : (uint128)val;
+			int128 val = *arg;
+			return (*is_neg = val < 0) ? (~(uint128)val) + 1 : (uint128)val;
 		case char:
 			return *arg;
 		case ushort:
@@ -63,21 +58,21 @@ fn uint128! int_from_variant(variant arg, bool *is_neg) @private
 			double d = *arg;
 			return (uint128)((*is_neg = d < 0) ? -d : d);
 		default:
-			return PrintFault.INVALID_ARGUMENT_TYPE!;
+			return PrintFault.INVALID_ARGUMENT_TYPE?;
 	}
 }

-fn FloatType! float_from_variant(variant arg) @private
+fn FloatType! float_from_any(any* arg) @private
 {
-	$if (env::F128_SUPPORT)
+	$if env::F128_SUPPORT:
 		if (arg.type == float128.typeid) return (FloatType)*((float128*)arg.ptr);
 	$endif
-	$if (env::F16_SUPPORT)
+	$if env::F16_SUPPORT:
 		if (arg.type == float16.typeid) return *((float16*)arg.ptr);
 	$endif
 	if (arg.type.kindof == TypeKind.DISTINCT)
 	{
-		return float_from_variant(variant { arg.ptr, arg.type.inner });
+		return float_from_any(arg.as_inner());
 	}
 	switch (arg)
 	{
@@ -92,7 +87,7 @@ fn FloatType! float_from_variant(variant arg) @private
 		case long:
 			return *arg;
 		case int128:
-    	    return *arg;
+			return *arg;
 		case char:
 			return *arg;
 		case ushort:
@@ -102,13 +97,13 @@ fn FloatType! float_from_variant(variant arg) @private
 		case ulong:
 			return *arg;
 		case uint128:
-            return *arg;
+			return *arg;
 		case float:
 			return (FloatType)*arg;
 		case double:
 			return (FloatType)*arg;
 		default:
-			return PrintFault.INVALID_ARGUMENT_TYPE!;
+			return PrintFault.INVALID_ARGUMENT_TYPE?;
 	}
 }

@@ -126,22 +121,21 @@ fn uint simple_atoi(char* buf, usz maxlen, usz* len_ptr) @inline @private
 	uint i = 0;
 	usz len = *len_ptr;
 	while (len < maxlen)
-    {
-        char c = buf[len];
-        if (c < '0' || c > '9') break;
-        i = i * 10 + c - '0';
-        len++;
-    }
-    *len_ptr = len;
-    return i;
+	{
+		char c = buf[len];
+		if (!c.is_digit()) break;
+		i = i * 10 + c - '0';
+		len++;
+	}
+	*len_ptr = len;
+	return i;
 }

-fn void! Formatter.out_substr(Formatter *this, String str) @private
+fn usz! Formatter.out_substr(&self, String str) @private
 {
 	usz l = conv::utf8_codepoints(str);
-	uint prec = this.prec;
-	if (this.flags.precision && l < prec) l = prec;
-	this.right_adjust(' ')?;
+	uint prec = self.prec;
+	if (self.flags.precision && l < prec) l = prec;
 	usz index = 0;
 	usz chars = str.len;
 	char* ptr = str.ptr;
@@ -149,16 +143,18 @@ fn void! Formatter.out_substr(Formatter *this, String str) @private
 	{
 		char c = ptr[index];
 		// Break if we have precision set and we ran out...
-		if (c & 0xC0 != 0x80 && this.flags.precision && !prec--) break;
-		this.out(c)?;
-        index++;
+		if (c & 0xC0 != 0x80 && self.flags.precision && !prec--) break;
+		self.out(c)!;
+		index++;
 	}
-	return this.left_adjust(l);
+	return index;
 }

-fn void! Formatter.pad(Formatter* this, char c, isz width, isz len) @inline
+fn usz! Formatter.pad(&self, char c, isz width, isz len) @inline
 {
-	for (isz i = len; i < width; i++) this.out(c)?;
+	isz delta = width - len;
+	for (isz i = 0; i < delta; i++) self.out(c)!;
+	return max(0, delta);
 }

 fn char* fmt_u(uint128 x, char* s)
@@ -168,9 +164,10 @@ fn char* fmt_u(uint128 x, char* s)
 	return s;
 }

-fn void! Formatter.out_chars(Formatter* this, char[] s)
+fn usz! Formatter.out_chars(&self, char[] s)
 {
-	foreach (c : s) this.out(c)?;
+	foreach (c : s) self.out(c)!;
+	return s.len;
 }

 enum FloatFormatting
@@ -181,35 +178,37 @@ enum FloatFormatting
 	HEX
 }

-fn void! Formatter.etoa(Formatter* this, double y) => this.floatformat(EXPONENTIAL, y);
-fn void! Formatter.ftoa(Formatter* this, double y) => this.floatformat(FLOAT, y);
-fn void! Formatter.gtoa(Formatter* this, double y) => this.floatformat(ADAPTIVE, y);
-fn void! Formatter.atoa(Formatter* this, double y) => this.floatformat(HEX, y);
+fn usz! Formatter.etoa(&self, double y) => self.floatformat(EXPONENTIAL, y);
+fn usz! Formatter.ftoa(&self, double y) => self.floatformat(FLOAT, y);
+fn usz! Formatter.gtoa(&self, double y) => self.floatformat(ADAPTIVE, y);
+fn usz! Formatter.atoa(&self, double y) => self.floatformat(HEX, y);

-fn void! Formatter.floatformat(Formatter* this, FloatFormatting formatting, double y) @private
+fn usz! Formatter.floatformat(&self, FloatFormatting formatting, double y) @private
 {
 	// This code is heavily based on musl's printf code
 	const BUF_SIZE = (math::DOUBLE_MANT_DIG + 28) / 29 + 1
 		+ (math::DOUBLE_MAX_EXP + math::DOUBLE_MANT_DIG + 28 + 8) / 9;
 	uint[BUF_SIZE] big;
-    bool is_neg = false;
-    if (math::signbit(y))
-    {
-        is_neg = true;
-        y = -y;
-    }
-    int pl = is_neg || this.flags.plus ? 1 : 0;
-    // Print inf/nan
+	bool is_neg = false;
+	if (math::signbit(y))
+	{
+		is_neg = true;
+		y = -y;
+	}
+	isz pl = is_neg || self.flags.plus ? 1 : 0;
+	// Print inf/nan
 	if (!math::is_finite(y))
 	{
+		usz len;
 		// Add padding
-		if (!this.flags.left) this.pad(' ', this.width, 3 + pl)?;
-		String s = this.flags.uppercase ? "INF" : "inf";
-		if (y != y) this.flags.uppercase ? "NAN" : "nan";
-		if (pl) this.out(is_neg ? '-' : '+')?;
-		this.out_chars(s)?;
-		if (this.flags.left) this.pad(' ', this.width, 3 + pl)?;
-		return;
+		if (!self.flags.left) len += self.pad(' ', self.width, 3 + pl)!;
+		String s = self.flags.uppercase ? "INF" : "inf";
+		if (y != y) s = self.flags.uppercase ? "NAN" : "nan";
+		len += s.len;
+		if (pl) len += self.out(is_neg ? '-' : '+')!;
+		len += self.out_chars(s)!;
+		if (self.flags.left) len += self.pad(' ', self.width, 3 + pl)!;
+		return len;
 	}
 	// Rescale
 	int e2;
@@ -220,7 +219,7 @@ fn void! Formatter.floatformat(Formatter* this, FloatFormatting formatting, doub
 	char* ebuf = 12 + (char*)&ebuf0;
 	char[9 + math::DOUBLE_MANT_DIG / 4] buf_array;
 	char* buf = &buf_array;
-	isz p = this.flags.precision ? this.prec : -1;
+	isz p = self.flags.precision ? self.prec : -1;
 	if (formatting == HEX)
 	{
 		double round = 8.0;
@@ -229,50 +228,51 @@ fn void! Formatter.floatformat(Formatter* this, FloatFormatting formatting, doub
 		if (p > 0 && p < math::DOUBLE_MANT_DIG / 4 - 1)
 		{
 			int re = math::DOUBLE_MANT_DIG / 4 - 1 - (int)p;
-    		round *= 1 << (math::DOUBLE_MANT_DIG % 4);
-    		while (re--) round *= 16;
-    		if (is_neg)
-    		{
-    		    y = -y;
+			round *= 1 << (math::DOUBLE_MANT_DIG % 4);
+			while (re--) round *= 16;
+			if (is_neg)
+			{
+				y = -y;
 				y -= round;
-    			y += round;
-    			y = -y;
-    		}
-    		else
-    		{
-    		    y += round;
-    			y -= round;
-    		}
+				y += round;
+				y = -y;
+			}
+			else
+			{
+				y += round;
+				y -= round;
+			}
 		}
 		// Reverse print
 		char* estr = fmt_u(e2 < 0 ? (int128)-e2 : (int128)e2, ebuf);
 		if (estr == ebuf) *--estr = '0';
 		*--estr = (e2 < 0 ? '-' : '+');
-		*--estr = this.flags.uppercase ? 'P' : 'p';
+		*--estr = self.flags.uppercase ? 'P' : 'p';
 		char* s = buf;
-		char* xdigits = this.flags.uppercase ? &XDIGITS_H : &XDIGITS_L;
+		char* xdigits = self.flags.uppercase ? &XDIGITS_H : &XDIGITS_L;
 		do
 		{
 			int x = (int)y;
 			*s++ = xdigits[x];
 			y = 16 * (y - x);
-			if (s - buf == 1 && (y || p > 0 || this.flags.hash)) *s++ = '.';
+			if (s - buf == 1 && (y || p > 0 || self.flags.hash)) *s++ = '.';
 		} while (y);
 		isz outlen = s - buf;
 		isz explen = ebuf - estr;
-		if (p > int.max - 2 - explen - pl) return PrintFault.INTERNAL_BUFFER_EXCEEDED!;
+		if (p > int.max - 2 - explen - pl) return PrintFault.INTERNAL_BUFFER_EXCEEDED?;
+		usz len;
 		usz l = p && outlen - 2 < p
 				? p + 2 + explen
 				: outlen + explen;
-		if (!this.flags.left && !this.flags.zeropad) this.pad(' ', this.width, pl + l)?;
-		if (is_neg || this.flags.plus) this.out(is_neg ? '-' : '+')?;
-		this.out_chars(this.flags.uppercase ? "0X" : "0x")?;
-		if (this.flags.zeropad) this.pad('0', this.width, pl + l)?;
-		this.out_chars(buf[:outlen])?;
-		this.pad('0', l - outlen - explen, 0)?;
-		this.out_chars(estr[:explen])?;
-		if (this.flags.left) this.pad(' ', this.width, pl + l)?;
-		return;
+		if (!self.flags.left && !self.flags.zeropad) len += self.pad(' ', self.width, pl + l)!;
+		if (is_neg || self.flags.plus) len += self.out(is_neg ? '-' : '+')!;
+		len += self.out_chars(self.flags.uppercase ? "0X" : "0x")!;
+		if (self.flags.zeropad) len += self.pad('0', self.width, pl + l)!;
+		len += self.out_chars(buf[:outlen])!;
+		len += self.pad('0', l - outlen - explen, 0)!;
+		len += self.out_chars(estr[:explen])!;
+		if (self.flags.left) len += self.pad(' ', self.width, pl + l)!;
+		return len;
 	}
 	if (p < 0) p = 6;
 	if (y)
@@ -405,7 +405,7 @@ fn void! Formatter.floatformat(Formatter* this, FloatFormatting formatting, doub
 			formatting = EXPONENTIAL;
 			p--;
 		}
-		if (!this.flags.hash)
+		if (!self.flags.hash)
 		{
 			// Count trailing zeros in last place
 			if (z > a && z[-1])
@@ -427,12 +427,12 @@ fn void! Formatter.floatformat(Formatter* this, FloatFormatting formatting, doub
 			}
 		}
 	}
-	if (p > int.max - 1 - (isz)(p || this.flags.hash)) return PrintFault.INTERNAL_BUFFER_EXCEEDED!;
-	int l = (int)(1 + p + (isz)(p || this.flags.hash));
+	if (p > int.max - 1 - (isz)(p || self.flags.hash)) return PrintFault.INTERNAL_BUFFER_EXCEEDED?;
+	int l = (int)(1 + p + (isz)(p || self.flags.hash));
 	char* estr @noinit;
 	if (formatting == FLOAT)
 	{
-		if (e > int.max - l) return PrintFault.INTERNAL_BUFFER_EXCEEDED!;
+		if (e > int.max - l) return PrintFault.INTERNAL_BUFFER_EXCEEDED?;
 		if (e > 0) l += e;
 	}
 	else
@@ -440,14 +440,15 @@ fn void! Formatter.floatformat(Formatter* this, FloatFormatting formatting, doub
 		estr = fmt_u((uint128)(e < 0 ? -e : e), ebuf);
 		while (ebuf - estr < 2) (--estr)[0] = '0';
 		*--estr = (e < 0 ? '-' : '+');
-		*--estr = this.flags.uppercase ? 'E' : 'e';
-		if (ebuf - estr > (isz)int.max - l) return PrintFault.INTERNAL_BUFFER_EXCEEDED!;
+		*--estr = self.flags.uppercase ? 'E' : 'e';
+		if (ebuf - estr > (isz)int.max - l) return PrintFault.INTERNAL_BUFFER_EXCEEDED?;
 		l += (int)(ebuf - estr);
 	}
-	if (l > int.max - pl) return PrintFault.INTERNAL_BUFFER_EXCEEDED!;
-	if (!this.flags.left && !this.flags.zeropad) this.pad(' ', this.width, pl + l)?;
-	if (is_neg || this.flags.plus) this.out(is_neg ? '-' : '+')?;
-	if (this.flags.zeropad) this.pad('0', this.width, pl + l)?;
+	if (l > int.max - pl) return PrintFault.INTERNAL_BUFFER_EXCEEDED?;
+	usz len;
+	if (!self.flags.left && !self.flags.zeropad) len += self.pad(' ', self.width, pl + l)!;
+	if (is_neg || self.flags.plus) len += self.out(is_neg ? '-' : '+')!;
+	if (self.flags.zeropad) len += self.pad('0', self.width, pl + l)!;
 	if (formatting == FLOAT)
 	{
 		if (a > r) a = r;
@@ -462,106 +463,106 @@ fn void! Formatter.floatformat(Formatter* this, FloatFormatting formatting, doub
 				case s == buf + 9:
 					*--s = '0';
 			}
-			this.out_chars(s[:buf + 9 - s])?;
+			len += self.out_chars(s[:buf + 9 - s])!;
 		}
-		if (p || this.flags.hash) this.out('.')?;
+		if (p || self.flags.hash) len += self.out('.')!;
 		for (; d < z && p > 0; d++, p -= 9)
 		{
 			char* s = fmt_u(*d, buf + 9);
 			while (s > buf) *--s = '0';
-			this.out_chars(s[:math::min((isz)9, p)])?;
+			len += self.out_chars(s[:math::min((isz)9, p)])!;
 		}
-		this.pad('0', p + 9, 9)?;
+		len += self.pad('0', p + 9, 9)!;
 	}
 	else
 	{
 		if (z <= a) z = a + 1;
-    	for (uint* d = a; d < z && p >= 0; d++)
-    	{
+		for (uint* d = a; d < z && p >= 0; d++)
+		{
 			char* s = fmt_u(*d, buf + 9);
 			if (s == buf + 9) (--s)[0] = '0';
-    		if (d != a)
-    		{
-    		    while (s > buf) (--s)[0] = '0';
-    		}
-    		else
-    		{
-    		    this.out(s++[0])?;
-    		    if (p > 0 || this.flags.hash) this.out('.')?;
-    		}
-    		this.out_chars(s[:math::min(buf + 9 - s, p)])?;
-    		p -= buf + 9 - s;
-    	}
-    	this.pad('0', p + 18, 18)?;
-    	this.out_chars(estr[:ebuf - estr])?;
+			if (d != a)
+			{
+				while (s > buf) (--s)[0] = '0';
+			}
+			else
+			{
+				len += self.out(s++[0])!;
+				if (p > 0 || self.flags.hash) len += self.out('.')!;
+			}
+			len += self.out_chars(s[:math::min(buf + 9 - s, p)])!;
+			p -= buf + 9 - s;
+		}
+		len += self.pad('0', p + 18, 18)!;
+		len += self.out_chars(estr[:ebuf - estr])!;
 	}

-	if (this.flags.left) this.pad(' ', this.width, pl + l)?;
+	if (self.flags.left) len += self.pad(' ', self.width, pl + l)!;

-	return;
+	return len;
 }

-fn void! Formatter.ntoa(Formatter* this, uint128 value, bool negative, uint base) @private
+fn usz! Formatter.ntoa(&self, uint128 value, bool negative, uint base) @private
 {
 	char[PRINTF_NTOA_BUFFER_SIZE] buf @noinit;
-	usz len = 0;
+	usz len;

 	// no hash for 0 values
-	if (!value) this.flags.hash = false;
+	if (!value) self.flags.hash = false;

 	// write if precision != 0 or value is != 0
-	if (!this.flags.precision || value)
+	if (!self.flags.precision || value)
 	{
-		char past_10 = (this.flags.uppercase ? 'A' : 'a') - 10;
+		char past_10 = (self.flags.uppercase ? 'A' : 'a') - 10;
 		do
 		{
-			if (len >= PRINTF_NTOA_BUFFER_SIZE) return PrintFault.INTERNAL_BUFFER_EXCEEDED!;
+			if (len >= PRINTF_NTOA_BUFFER_SIZE) return PrintFault.INTERNAL_BUFFER_EXCEEDED?;
 			char digit = (char)(value % base);
 			buf[len++] = digit + (digit < 10 ? '0' : past_10);
 			value /= base;
 		}
 		while (value);
 	}
-	return this.ntoa_format((String)buf[:PRINTF_NTOA_BUFFER_SIZE], len, negative, base);
+	return self.ntoa_format((String)buf[:PRINTF_NTOA_BUFFER_SIZE], len, negative, base);
 }

-fn void! Formatter.ntoa_format(Formatter* this, String buf, usz len, bool negative, uint base) @private
+fn usz! Formatter.ntoa_format(&self, String buf, usz len, bool negative, uint base) @private
 {
 	// pad leading zeros
-	if (!this.flags.left)
+	if (!self.flags.left)
 	{
-		if (this.width && this.flags.zeropad && (negative || this.flags.plus || this.flags.space)) this.width--;
-		while (len < this.prec)
+		if (self.width && self.flags.zeropad && (negative || self.flags.plus || self.flags.space)) self.width--;
+		while (len < self.prec)
 		{
-			if (len >= buf.len) return PrintFault.INTERNAL_BUFFER_EXCEEDED!;
+			if (len >= buf.len) return PrintFault.INTERNAL_BUFFER_EXCEEDED?;
 			buf[len++] = '0';
 		}
-		while (this.flags.zeropad && len < this.width)
+		while (self.flags.zeropad && len < self.width)
 		{
-			if (len >= buf.len) return PrintFault.INTERNAL_BUFFER_EXCEEDED!;
+			if (len >= buf.len) return PrintFault.INTERNAL_BUFFER_EXCEEDED?;
 			buf[len++] = '0';
 		}
 	}

 	// handle hash
-	if (this.flags.hash && base != 10)
+	if (self.flags.hash && base != 10)
 	{
-		if (!this.flags.precision && len && len == this.prec && len == this.width)
+		if (!self.flags.precision && len && len == self.prec && len == self.width)
 		{
 			len--;
 			if (len) len--;
 		}
 		if (base != 10)
 		{
-			if (len + 1 >= buf.len) return PrintFault.INTERNAL_BUFFER_EXCEEDED!;
+			if (len + 1 >= buf.len) return PrintFault.INTERNAL_BUFFER_EXCEEDED?;
 			switch (base)
 			{
 				case 16:
-					buf[len++] = this.flags.uppercase ? 'X' : 'x';
+					buf[len++] = self.flags.uppercase ? 'X' : 'x';
 				case 8:
-					buf[len++] = this.flags.uppercase ? 'O' : 'o';
+					buf[len++] = self.flags.uppercase ? 'O' : 'o';
 				case 2:
-					buf[len++] = this.flags.uppercase ? 'B' : 'b';
+					buf[len++] = self.flags.uppercase ? 'B' : 'b';
 				default:
 					unreachable();
 			}
@@ -572,96 +573,97 @@ fn void! Formatter.ntoa_format(Formatter* this, String buf, usz len, bool negati
 	switch (true)
 	{
 		case negative:
-			if (len >= buf.len) return PrintFault.INTERNAL_BUFFER_EXCEEDED!;
+			if (len >= buf.len) return PrintFault.INTERNAL_BUFFER_EXCEEDED?;
 			buf[len++] = '-';
-		case this.flags.plus:
-			if (len >= buf.len) return PrintFault.INTERNAL_BUFFER_EXCEEDED!;
+		case self.flags.plus:
+			if (len >= buf.len) return PrintFault.INTERNAL_BUFFER_EXCEEDED?;
 			buf[len++] = '+';
-		case this.flags.space:
-			if (len >= buf.len) return PrintFault.INTERNAL_BUFFER_EXCEEDED!;
+		case self.flags.space:
+			if (len >= buf.len) return PrintFault.INTERNAL_BUFFER_EXCEEDED?;
 			buf[len++] = ' ';
 	}
-	if (!len) return;
-	return this.out_reverse(buf[:len]);
+	if (len) self.out_reverse(buf[:len])!;
+	return len;
 }


-fn void! Formatter.ntoa_variant(Formatter* this, variant arg, uint base) @private
+fn usz! Formatter.ntoa_any(&self, any* arg, uint base) @private
 {
 	bool is_neg;
-	uint128 val = int_from_variant(arg, &is_neg)!!;
-	return this.ntoa(val, is_neg, base) @inline;
+	uint128 val = int_from_any(arg, &is_neg)!!;
+	return self.ntoa(val, is_neg, base) @inline;
 }

-fn void! Formatter.out_char(Formatter* this, variant arg) @private
+fn usz! Formatter.out_char(&self, any* arg) @private
 {
+	usz len = 1;
 	uint l = 1;
 	// pre padding
-	this.right_adjust(l)?;
-    // char output
-    Char32 c = types::variant_to_int(arg, uint) ?? 0xFFFD;
+	len += self.adjust(l)!;
+	// char output
+	Char32 c = types::any_to_int(arg, uint) ?? 0xFFFD;
 	switch (true)
 	{
 		case c < 0x7f:
-			this.out((char)c)?;
+			self.out((char)c)!;
 		case c < 0x7ff:
-			this.out((char)(0xC0 | c >> 6))?;
-			this.out((char)(0x80 | (c & 0x3F)))?;
-        case c < 0xffff:
-			this.out((char)(0xE0 | c >> 12))?;
-			this.out((char)(0x80 | (c >> 6 & 0x3F)))?;
-			this.out((char)(0x80 | (c & 0x3F)))?;
-        default:
-			this.out((char)(0xF0 | c >> 18))?;
-			this.out((char)(0x80 | (c >> 12 & 0x3F)))?;
-			this.out((char)(0x80 | (c >> 6 & 0x3F)))?;
-			this.out((char)(0x80 | (c & 0x3F)))?;
+			self.out((char)(0xC0 | c >> 6))!;
+			self.out((char)(0x80 | (c & 0x3F)))!;
+		case c < 0xffff:
+			self.out((char)(0xE0 | c >> 12))!;
+			self.out((char)(0x80 | (c >> 6 & 0x3F)))!;
+			self.out((char)(0x80 | (c & 0x3F)))!;
+		default:
+			self.out((char)(0xF0 | c >> 18))!;
+			self.out((char)(0x80 | (c >> 12 & 0x3F)))!;
+			self.out((char)(0x80 | (c >> 6 & 0x3F)))!;
+			self.out((char)(0x80 | (c & 0x3F)))!;
 	}
-	return this.left_adjust(l);
+	len += self.adjust(l)!;
+	return len;
 }


-fn void! Formatter.out_reverse(Formatter* this, char[] buf) @private
+fn usz! Formatter.out_reverse(&self, char[] buf) @private
 {
-	usz buffer_start_idx = this.idx;
+	usz n;
+	usz buffer_start_idx = self.idx;
 	usz len = buf.len;
-    // pad spaces up to given width
-    if (!this.flags.left && !this.flags.zeropad)
-    {
-        for (usz i = len; i < this.width; i++)
-        {
-            this.out(' ')?;
-        }
-    }
-    // reverse string
-    while (len) this.out(buf[--len])?;
+	// pad spaces up to given width
+	if (!self.flags.zeropad)
+	{
+		n += self.adjust(len)!;
+	}
+	// reverse string
+	while (len) n += self.out(buf[--len])!;

 	// append pad spaces up to given width
-	return this.left_adjust(this.idx - buffer_start_idx);
+	n += self.adjust(self.idx - buffer_start_idx)!;
+	return n;
 }

 fn void! printf_advance_format(usz format_len, usz *index_ptr) @inline @private
 {
 	usz val = ++(*index_ptr);
-	if (val >= format_len) return FormattingFault.UNTERMINATED_FORMAT!;
+	if (val >= format_len) return FormattingFault.UNTERMINATED_FORMAT?;
 }

-fn variant! next_variant(variant* args_ptr, usz args_len, usz* arg_index_ptr) @inline @private
+fn any*! next_any(any** args_ptr, usz args_len, usz* arg_index_ptr) @inline @private
 {
-	if (*arg_index_ptr >= args_len) return FormattingFault.MISSING_ARG!;
+	if (*arg_index_ptr >= args_len) return FormattingFault.MISSING_ARG?;
 	return args_ptr[(*arg_index_ptr)++];
 }

 fn int! printf_parse_format_field(
-	variant* args_ptr, usz args_len, usz* args_index_ptr,
+	any** args_ptr, usz args_len, usz* args_index_ptr,
 	char* format_ptr, usz format_len, usz* index_ptr) @inline @private
 {
 	char c = format_ptr[*index_ptr];
-	if (c >= '0' && c <= '9') return simple_atoi(format_ptr, format_len, index_ptr);
+	if (c.is_digit()) return simple_atoi(format_ptr, format_len, index_ptr);
 	if (c != '*') return 0;
-	printf_advance_format(format_len, index_ptr)?;
-	variant val = next_variant(args_ptr, args_len, args_index_ptr)?;
-    if (!val.type.kindof.is_int()) return FormattingFault.INVALID_WIDTH_ARG!;
-    uint! intval = types::variant_to_int(val, int);
-	return intval ?? FormattingFault.INVALID_WIDTH_ARG!;
+	printf_advance_format(format_len, index_ptr)!;
+	any* val = next_any(args_ptr, args_len, args_index_ptr)!;
+	if (!val.type.kindof.is_int()) return FormattingFault.INVALID_WIDTH_ARG?;
+	uint! intval = types::any_to_int(val, int);
+	return intval ?? FormattingFault.INVALID_WIDTH_ARG?;
 }
--- a/lib/std/io/io.c3
+++ b/lib/std/io/io.c3
@@ -4,136 +4,287 @@
 module std::io;
 import libc;

-struct File
-{
-    CFile file;
-}
-
 enum Seek
 {
-    SET,
-    CURSOR,
-    END
+	SET,
+	CURSOR,
+	END
 }

 fault IoError
 {
-    FILE_NOT_FOUND,
-    FILE_NOT_VALID,
-    INVALID_POSITION,
-    OVERFLOW,
-    FILE_IS_PIPE,
-    FILE_EOF,
-    INCOMPLETE_WRITE,
-    NO_PERMISSION,
-    OUT_OF_SPACE,
-    INVALID_PUSHBACK,
-    EOF,
-    CANNOT_READ_DIR,
-    TOO_MANY_DESCRIPTORS,
-    FILE_IS_DIR,
-    READ_ONLY,
-    FILE_NOT_DIR,
-    SYMLINK_FAILED,
-    ALREADY_EXISTS,
-    NOT_SEEKABLE,
-    NAME_TOO_LONG,
-    WOULD_BLOCK,
-    INTERRUPTED,
-    GENERAL_ERROR,
-    UNKNOWN_ERROR,
-    UNSUPPORTED_OPERATION,
+	ALREADY_EXISTS,
+	BUSY,
+	CANNOT_READ_DIR,
+	DIR_NOT_EMPTY,
+	EOF,
+	FILE_CANNOT_DELETE,
+	FILE_IS_DIR,
+	FILE_IS_PIPE,
+	FILE_NOT_DIR,
+	FILE_NOT_FOUND,
+	FILE_NOT_VALID,
+	GENERAL_ERROR,
+	ILLEGAL_ARGUMENT,
+	INCOMPLETE_WRITE,
+	INTERRUPTED,
+	INVALID_POSITION,
+	INVALID_PUSHBACK,
+	NAME_TOO_LONG,
+	NOT_SEEKABLE,
+	NO_PERMISSION,
+	OUT_OF_SPACE,
+	OVERFLOW,
+	READ_ONLY,
+	SYMLINK_FAILED,
+	TOO_MANY_DESCRIPTORS,
+	UNEXPECTED_EOF,
+	UNKNOWN_ERROR,
+	UNSUPPORTED_OPERATION,
+	WOULD_BLOCK,
 }

-fn void putchar(char c) @inline
+
+/**
+ * @param stream
+ * @require @is_instream(stream)
+ **/
+macro String! readline(stream = io::stdin(), Allocator* allocator = mem::heap())
 {
-    libc::putchar(c);
+	bool $is_stream = @typeid(stream) == InStream*.typeid;
+	$if $is_stream:
+		$typeof(&stream.read_byte) func = &stream.read_byte;
+		char val = func((void*)stream)!;
+	$else
+		char val = stream.read_byte()!;
+	$endif
+
+    if (val == '\n') return "";
+    @pool(allocator)
+    {
+        DString str = dstring::temp_with_capacity(256);
+    	if (val != '\r') str.append(val);
+    	while (1)
+    	{
+    	    $if $is_stream:
+    	        char! c = func((void*)stream);
+    	    $else
+    	        char! c = stream.read_byte();
+    	    $endif
+    		if (catch err = c)
+    		{
+    			if (err == IoError.EOF) break;
+    			return err?;
+    		}
+    		if (c == '\r') continue;
+    		if (c == '\n') break;
+    		str.append_char(c);
+    	}
+    	return str.copy_str(allocator);
+    };
+}
+
+macro String! treadline(stream = io::stdin()) => readline(stream, mem::temp()) @inline;
+
+/**
+ * @require @is_outstream(out) "The output must implement OutStream"
+ */
+macro usz! fprint(out, x)
+{
+	var $Type = $typeof(x);
+	$switch ($Type)
+	$case String:
+		return out.write(x);
+	$case ZString:
+		return out.write(x.str_view());
+	$case DString:
+		return out.write(x.str_view());
+	$default:
+		$if $assignable(x, String):
+			return out.write((String)x);
+		$else
+			return fprintf(out, "%s", x);
+		$endif
+	$endswitch
+}
+
+fn usz! fprintf(OutStream* out, String format, args...)
+{
+	Formatter formatter;
+	formatter.init(&out_putstream_fn, &out);
+	return formatter.vprintf(format, args);
+}
+
+fn usz! fprintfn(OutStream* out, String format, args...) @maydiscard
+{
+	Formatter formatter;
+	formatter.init(&out_putstream_fn, &out);
+	usz len = formatter.vprintf(format, args)!;
+	out.write_byte('\n')!;
+	if (&out.flush) out.flush()!;
+	return len + 1;
+}
+
+/**
+ * @require @is_outstream(out) "The output must implement OutStream"
+ */
+macro usz! fprintn(out, x = "")
+{
+	usz len = fprint(out, x)!;
+	out.write_byte('\n')!;
+	$switch
+		$case @typeid(out) == OutStream*.typeid:
+			if (&out.flush) out.flush()!;
+		$case $defined(out.flush):
+			out.flush()!;
+	$endswitch
+	return len + 1;
 }

 macro void print(x)
 {
-	var $Type = $typeof(x);
-	$switch ($Type)
-	$case String:
-		catch? stdout().print(x);
-	$case ZString:
-		catch? stdout().print(x.as_str());
-	$case DString:
-		catch? stdout().print(x.str());
-	$case VarString:
-		catch? stdout().print(x.str());
-	$default:
-		$if (@convertible(x, String))
-			catch? stdout().print((String)x);
-		$else
-			catch? stdout().printf("%s", x);
-		$endif
-	$endswitch
+	(void)fprint(io::stdout(), x);
 }

 macro void printn(x = "")
 {
-	var $Type = $typeof(x);
-	$switch ($Type)
-	$case String:
-		catch? stdout().printn(x);
-	$case ZString:
-		catch? stdout().printn(x.as_str());
-	$case DString:
-		catch? stdout().printn(x.str());
-	$case VarString:
-		catch? stdout().printn(x.str());
-	$default:
-		$if (@convertible(x, String))
-			catch? stdout().printn((String)x);
-		$else
-			catch? stdout().printfn("%s", x);
-		$endif
-	$endswitch
+	(void)fprintn(io::stdout(), x);
 }

-macro void println(x = "") @deprecated => printn(x);
-
-fn File stdout()
+macro void eprint(x)
 {
-	return { libc::stdout() };
+	(void)fprint(io::stderr(), x);
 }

-fn File stderr()
+macro void eprintn(x)
 {
-	return { libc::stderr() };
+	(void)fprintn(io::stderr(), x);
 }

-fn File stdin()
+
+fn void! out_putstream_fn(void* data, char c) @private
 {
-	return { libc::stdin() };
+	OutStream** stream = data;
+	return (*stream).write_byte(c);
 }

-/*
-
-
-error FileError
+fn void! out_putchar_fn(void* data @unused, char c) @private
 {
-    ulong errno;
+	libc::putchar(c);
 }

-fn FileError errorFromErrno()
+fn usz! printf(String format, args...) @maydiscard
 {
-    return FileError { };
+	Formatter formatter;
+	formatter.init(&out_putchar_fn);
+	return formatter.vprintf(format, args);
 }

-
-
-
-pubic fn void! File.clearerr(File *file) @inline
+fn usz! printfn(String format, args...) @maydiscard
 {
-    clearerr(file->file);
+	Formatter formatter;
+	formatter.init(&out_putchar_fn);
+	usz len = formatter.vprintf(format, args)!;
+	putchar('\n');
+	io::stdout().flush()!;
+	return len + 1;
 }

-
-
-fn void File.error(File *file) @inline
+fn usz! eprintf(String format, args...) @maydiscard
 {
-    int err = ferror
+	Formatter formatter;
+	OutStream* stream = stderr();
+	formatter.init(&out_putstream_fn, &stream);
+	return formatter.vprintf(format, args);
+}
+
+
+fn usz! eprintfn(String format, args...) @maydiscard
+{
+	Formatter formatter;
+	OutStream* stream = stderr();
+	formatter.init(&out_putstream_fn, &stream);
+	usz len = formatter.vprintf(format, args)! + 1;
+	stderr().write_byte('\n')!;
+	stderr().flush()!;
+	return len;
+}
+
+fn char[]! bprintf(char[] buffer, String format, args...) @maydiscard
+{
+	Formatter formatter;
+	BufferData data = { .buffer = buffer };
+	formatter.init(&out_buffer_fn, &data);
+	usz size = formatter.vprintf(format, args)!;
+	return buffer[:data.written];
+}
+
+fn void! out_buffer_fn(void *data, char c) @private
+{
+	BufferData *buffer_data = data;
+	if (buffer_data.written >= buffer_data.buffer.len) return PrintFault.BUFFER_EXCEEDED?;
+	buffer_data.buffer[buffer_data.written++] = c;
+}
+
+
+struct BufferData @private
+{
+	char[] buffer;
+	usz written;
+}
+
+
+module std::io @if (env::LIBC);
+import libc;
+
+fn void putchar(char c) @inline
+{
+	libc::putchar(c);
+}
+
+fn File* stdout()
+{
+	static File file;
+	if (!file.file) file = file::from_handle(libc::stdout());
+	return &file;
+}
+
+fn File* stderr()
+{
+	static File file;
+	if (!file.file) file = file::from_handle(libc::stderr());
+	return &file;
+}
+
+fn File* stdin()
+{
+	static File file;
+	if (!file.file) file = file::from_handle(libc::stdin());
+	return &file;
+}
+
+module std::io @if(!env::LIBC);
+
+File stdin_file;
+File stdout_file;
+File stderr_file;
+
+fn void putchar(char c) @inline
+{
+	(void)stdout_file.putc(c);
+}
+
+fn File* stdout()
+{
+	return &stdout_file;
+}
+
+fn File* stderr()
+{
+	return &stderr_file;
+}
+
+fn File* stdin()
+{
+	return &stdin_file;
 }
-*/
--- a/lib/std/io/io_file.c3
+++ b/lib/std/io/io_file.c3
@@ -1,173 +0,0 @@
-module std::io::file;
-import libc;
-
-fn File! open(String filename, String mode)
-{
-	return { .file = os::native_fopen(filename, mode) };
-}
-
-fn void! File.open(File* file, String filename, String mode) @deprecated
-{
-	file.file = os::native_fopen(filename, mode)?;
-}
-
-/**
- * @require file.file != null
- **/
-fn void! File.reopen(File* file, String filename, String mode)
-{
-	file.file = os::native_freopen(file.file, filename, mode)?;
-}
-
-/**
- * @require file.file != null
- **/
-fn usz! File.seek(File file, isz offset, Seek seek_mode = Seek.SET)
-{
-	os::native_fseek(file.file, offset, seek_mode)?;
-	return os::native_ftell(file.file);
-}
-
-
-/*
-Implement later
-/**
- * @require file.file == null
- **/
-fn void! File.memopen(File* file, char[] data, String mode)
-{
-	@pool()
-	{
-		file.file = libc::memopen(data.ptr, data.len, mode.zstr_tcopy(), file.file);
-		// TODO errors
-	};
-}
-*/
-
-
-/**
- * @require file && file.file != null
- */
-fn void! File.putc(File *file, char c)
-{
-    if (!libc::fputc(c, file.file)) return IoError.FILE_EOF!;
-}
-
-/**
- * @require file != null
- */
-fn void! File.close(File *file) @inline
-{
-    if (file.file && libc::fclose(file.file))
-    {
-        switch (libc::errno())
-        {
-            case errno::ECONNRESET:
-            case errno::EBADF: return IoError.FILE_NOT_VALID!;
-            case errno::EINTR: return IoError.INTERRUPTED!;
-            case errno::EDQUOT:
-            case errno::EFAULT:
-            case errno::EAGAIN:
-            case errno::EFBIG:
-            case errno::ENETDOWN:
-            case errno::ENETUNREACH:
-            case errno::ENOSPC:
-            case errno::EIO: return IoError.INCOMPLETE_WRITE!;
-            default: return IoError.UNKNOWN_ERROR!;
-        }
-    }
-    file.file = null;
-}
-
-/**
- * @require file && file.file
- */
-fn bool File.eof(File* file) @inline
-{
-    return libc::feof(file.file) != 0;
-}
-
-/**
- * @param [in] buffer
- */
-fn usz! File.read(File* file, char[] buffer)
-{
-	return os::native_fread(file.file, buffer);
-}
-
-/**
- * @param [&in] file
- * @param [&out] buffer
- * @require file.file `File must be initialized`
- */
-fn usz! File.write(File file, char[] buffer)
-{
-	return os::native_fwrite(file.file, buffer);
-}
-
-/**
- * @param [&in] file
- * @require file.file `File must be initialized`
- */
-fn usz! File.printn(File file, String string)
-{
-	usz len = file.print(string)?;
-	if (!libc::putc('\n', file.file)) return IoError.UNKNOWN_ERROR!;
-    return len + 1;
-}
-
-/**
- * @param [&in] file
- * @require file.file `File must be initialized`
- */
-fn usz! File.print(File file, String string)
-{
-    usz len = string.len;
-    if (len != file.write((char[])string)?) return IoError.UNKNOWN_ERROR!;
-    return len;
-}
-
-fn usz! File.println(File file, String string) @deprecated => file.printn(string);
-
-/**
- * @param [&in] file
- * @require file.file `File must be initialized`
- */
-fn DString File.getline(File* file, Allocator* using = mem::heap())
-{
-	DString s = dstring::new_with_capacity(120, using);
-	while (!file.eof())
-	{
-		int c = libc::fgetc(file.file);
-		if (c == -1) break;
-		if (c == '\n') break;
-		s.append_char((char)c);
-	}
-	return s;
-}
-
-/**
- * @param [&in] file
- * @require file.file `File must be initialized`
- * @return "a zero terminated String (the pointer may be safely cast into a ZString)"
- */
-fn String File.tgetline(File* file)
-{
-	return file.getline(mem::temp()).zstr().as_str();
-}
-
-fn char! File.getc(File* file)
-{
-	int c = libc::fgetc(file.file);
-	if (c == -1) return IoError.FILE_EOF!;
-	return (char)c;
-}
-
-/**
- * @param [&in] file
- * @require file.file `File must be initialized`
- */
-fn void File.flush(File* file)
-{
-	libc::fflush(file.file);
-}
--- a/lib/std/io/io_fileinfo.c3
+++ b/lib/std/io/io_fileinfo.c3
@@ -1,14 +0,0 @@
-module std::io::file;
-import libc;
-
-
-
-fn bool is_file(String path)
-{
-	return os::native_is_file(path);
-}
-
-fn usz! get_size(String path)
-{
-	return os::native_file_size(path);
-}
--- a/lib/std/io/io_printf.c3
+++ b/lib/std/io/io_printf.c3
@@ -1,502 +0,0 @@
-module std::io;
-import std::collections::map;
-import libc;
-
-const int PRINTF_NTOA_BUFFER_SIZE = 256;
-
-fault PrintFault
-{
-	BUFFER_EXCEEDED,
-	INTERNAL_BUFFER_EXCEEDED,
-	INVALID_FORMAT_STRING,
-	MISSING_ARG,
-	INVALID_ARGUMENT_TYPE,
-}
-
-fault FormattingFault
-{
-	UNTERMINATED_FORMAT,
-	MISSING_ARG,
-	INVALID_WIDTH_ARG,
-	INVALID_FORMAT_TYPE,
-}
-
-typedef OutputFn = fn void!(char c, void* buffer);
-typedef ToStringFunction = fn String(void* value, Allocator *using);
-typedef ToFormatFunction = fn void!(void* value, Formatter* formatter);
-typedef FloatType = double;
-
-fn usz! printf(String format, args...) @maydiscard
-{
-	Formatter formatter;
-	formatter.init(&out_putchar_fn);
-    return formatter.vprintf(format, args);
-}
-
-define printfln = printfn;
-
-fn usz! printfn(String format, args...) @maydiscard
-{
-	Formatter formatter;
-	formatter.init(&out_putchar_fn);
-    usz len = formatter.vprintf(format, args)?;
-	putchar('\n');
-	return len + 1;
-}
-
-fn usz! VarString.printf(VarString* str, String format, args...) @maydiscard
-{
-	Formatter formatter;
-	formatter.init(&out_string_append_fn, str);
-	return formatter.vprintf(format, args);
-}
-
-fn usz! VarString.printfn(VarString* str, String format, args...) @maydiscard
-{
-	Formatter formatter;
-	formatter.init(&out_string_append_fn, str);
-	usz len = formatter.vprintf(format, args)?;
-	str.append('\n');
-	return len + 1;
-}
-
-fn char[]! bprintf(char[] buffer, String format, args...) @maydiscard
-{
-	Formatter formatter;
-	BufferData data = { .buffer = buffer };
-    formatter.init(&out_buffer_fn, &data);
-    usz size = formatter.vprintf(format, args)?;
-    return buffer[:data.written];
-}
-
-fn usz! File.printf(File file, String format, args...) @maydiscard
-{
-	Formatter formatter;
-    formatter.init(&out_fputchar_fn, &file);
-    return formatter.vprintf(format, args)?;
-}
-
-fn usz! File.printfn(File file, String format, args...) @maydiscard
-{
-	Formatter formatter;
-    formatter.init(&out_fputchar_fn, &file);
-    usz len = formatter.vprintf(format, args)?;
-	file.putc('\n')?;
-	file.flush();
-	return len + 1;
-}
-
-fn usz! Formatter.printf(Formatter* this, String format, args...)
-{
-	return this.vprintf(format, args) @inline;
-}
-
-struct Formatter
-{
-	void *data;
-	OutputFn out_fn;
-	struct
-	{
-		PrintFlags flags;
-    	uint width;
-    	uint prec;
-    	usz idx;
-	}
-}
-
-bitstruct PrintFlags : uint
-{
-	bool zeropad : 0;
-	bool left : 1;
-	bool plus : 2;
-	bool space : 3;
-	bool hash : 4;
-	bool uppercase : 5;
-	bool precision : 6;
-}
-
-fn void Formatter.init(Formatter* this, OutputFn out_fn, void* data = null)
-{
-	*this = { .data = data, .out_fn = out_fn};
-}
-
-/**
- * @require $checks($Type a, a.to_string()) || $checks($Type a, a.to_format(&&Formatter{}))  "Expected a type with 'to_string' or 'to_format' defined"
- * @require !$checks($Type a, a.to_string()) || $checks($Type a, a.to_string(&&Allocator{})) "Expected 'to_string' to take an allocator as argument."
- * @require !$checks($Type a, a.to_format(&&Formatter{})) || $checks($Type a, Formatter b, a.to_format(&b)) "Expected 'to_format' to take a Formatter as argument."
- */
-macro void formatter_register_type($Type)
-{
-	$if ($checks($Type a, a.to_format(&&Formatter {})))
-		if (!toformat_functions.table.len)
-		{
-			toformat_functions.init(64);
-		}
-		toformat_functions.set($Type.typeid, (ToFormatFunction)&$Type.to_format);
-	$else
-		if (!tostring_functions.table.len)
-		{
-			tostring_functions.init(64);
-		}
-		tostring_functions.set($Type.typeid, (ToStringFunction)&$Type.to_string);
-	$endif
-}
-
-
-static initialize @priority(101)
-{
-	if (!toformat_functions.table.len)
-	{
-		toformat_functions.init(64);
-	}
-	if (!tostring_functions.table.len)
-	{
-		tostring_functions.init(64);
-	}
-}
-
-fn void! Formatter.out(Formatter* this, char c) @private
-{
-	this.out_fn(c, this.data)?;
-}
-
-macro bool! Formatter.print_with_function(Formatter* this, variant arg)
-{
-	if (try to_format = toformat_functions.get(arg.type))
-	{
-		PrintFlags old = this.flags;
-		uint old_width = this.width;
-		uint old_prec = this.prec;
-		defer
-		{
-			this.flags = old;
-			this.width = old_width;
-			this.prec = old_prec;
-		}
-		to_format(arg.ptr, this)?;
-		return true;
-    }
-    if (try to_string = tostring_functions.get(arg.type))
-    {
-		PrintFlags old = this.flags;
-		uint old_width = this.width;
-		uint old_prec = this.prec;
-		defer
-		{
-			this.flags = old;
-			this.width = old_width;
-			this.prec = old_prec;
-		}
-		@pool()
-		{
-			this.out_substr(to_string(arg.ptr, mem::temp()))?;
-			return true;
-		};
-    }
-    return false;
-}
-
-fn void! Formatter.out_str(Formatter* this, variant arg) @private
-{
-	switch (arg.type.kindof)
-	{
-		case TYPEID:
-			return this.out_substr("<typeid>");
-		case VOID:
-        	return this.out_substr("void");
-		case ANYERR:
-		case FAULT:
-        	return this.out_substr((*(anyerr*)arg.ptr).nameof);
-		case VARIANT:
-			return this.out_str(*(variant*)arg);
-		case ENUM:
-			if (this.print_with_function(arg)?) return;
-        	return this.out_substr(arg.type.names[types::variant_to_int(arg, usz)!!]);
-		case STRUCT:
-			if (this.print_with_function(arg)?) return;
-			return this.out_substr("<struct>");
-		case UNION:
-			if (this.print_with_function(arg)?) return;
-			return this.out_substr("<union>");
-		case BITSTRUCT:
-			if (this.print_with_function(arg)?) return;
-			return this.out_substr("<bitstruct>");
-		case FUNC:
-			if (this.print_with_function(arg)?) return;
-			return this.out_substr("<function>");
-		case OPTIONAL:
-			unreachable();
-		case DISTINCT:
-			if (this.print_with_function(arg)?) return;
-			if (arg.type == VarString.typeid)
-			{
-				return this.out_substr(((VarString*)arg).str());
-			}
-			if (arg.type == DString.typeid)
-			{
-				return this.out_substr(((DString*)arg).str());
-			}
-        	return this.out_str(variant { arg.ptr, arg.type.inner });
-		case POINTER:
-			if (this.print_with_function(arg)?) return;
-			return this.ntoa_variant(arg, 16);
-		case SIGNED_INT:
-		case UNSIGNED_INT:
-			return this.ntoa_variant(arg, 10);
-		case FLOAT:
-			return this.ftoa(float_from_variant(arg)!!);
-		case ARRAY:
-			if (this.print_with_function(arg)?) return;
-			// this is SomeType[*] so grab the "SomeType"
-			typeid inner = arg.type.inner;
-			usz size = inner.sizeof;
-			usz len = arg.type.len;
-			// Pretend this is a String
-			void* ptr = (void*)arg.ptr;
-			this.out('[')?;
-			for (usz i = 0; i < len; i++)
-			{
-				if (i != 0) this.out_substr(", ")?;
-				this.out_str(variant { ptr, inner })?;
-				ptr += size;
-			}
-			return this.out(']');
-		case VECTOR:
-			if (this.print_with_function(arg)?) return;
-			// this is SomeType[*] so grab the "SomeType"
-			typeid inner = arg.type.inner;
-			usz size = inner.sizeof;
-			usz len = arg.type.len;
-			// Pretend this is a String
-			void* ptr = (void*)arg.ptr;
-			this.out_substr("[<")?;
-			for (usz i = 0; i < len; i++)
-			{
-				if (i != 0) this.out_substr(", ")?;
-				this.out_str(variant { ptr, inner })?;
-				ptr += size;
-			}
-			return this.out_substr(">]");
-		case SUBARRAY:
-			if (this.print_with_function(arg)?) return;
-			// this is SomeType[] so grab the "SomeType"
-			typeid inner = arg.type.inner;
-			if (inner == char.typeid)
-			{
-				return this.out_substr(*(String*)arg);
-			}
-			usz size = inner.sizeof;
-            // Pretend this is a String
-			String* temp = (void*)arg.ptr;
-			void* ptr = (void*)temp.ptr;
-			usz len = temp.len;
-			this.out('[')?;
-			for (usz i = 0; i < len; i++)
-			{
-				if (i != 0) this.out_substr(", ")?;
-				this.out_str(variant { ptr, inner })?;
-				ptr += size;
-			}
-			this.out(']')?;
-		case BOOL:
-			if (*(bool*)arg.ptr)
-			{
-				return this.out_substr("true");
-			}
-			else
-			{
-				return this.out_substr("false");
-			}
-		default:
-			if (this.print_with_function(arg)?) return;
-			return this.out_substr("Invalid type");
-	}
-}
-
-
-
-fn void! out_buffer_fn(char c, void *data) @private
-{
-	BufferData *buffer_data = data;
-	if (buffer_data.written >= buffer_data.buffer.len) return PrintFault.BUFFER_EXCEEDED!;
-	buffer_data.buffer[buffer_data.written++] = c;
-}
-
-fn void! out_null_fn(char c @unused, void* data @unused) @private
-{
-}
-
-fn void! out_putchar_fn(char c, void* data @unused) @private
-{
-	libc::putchar(c);
-}
-
-fn void! out_fputchar_fn(char c, void* data) @private
-{
-	File* f = data;
-	f.putc(c)?;
-}
-
-fn void! out_string_append_fn(char c, void* data) @private
-{
-	VarString* s = data;
-	s.append_char(c);
-}
-
-
-struct BufferData @private
-{
-	char[] buffer;
-	usz written;
-}
-
-
-fn usz! Formatter.vprintf(Formatter* this, String format, variant[] variants)
-{
-	if (!this.out_fn)
-	{
-		// use null output function
-		this.out_fn = &out_null_fn;
-	}
-	usz format_len = format.len;
-	usz variant_index = 0;
-	for (usz i = 0; i < format_len; i++)
-	{
-		// format specifier?  %[flags][width][.precision][length]
-		char c = format[i];
-		if (c != '%')
-		{
-			// no
-			this.out(c)?;
-			continue;
-		}
-		i++;
-		if (i >= format_len) return PrintFault.INVALID_FORMAT_STRING!;
-		c = format[i];
-		if (c == '%')
-		{
-			this.out(c)?;
-			continue;
-		}
-		// evaluate flags
-		this.flags = {};
-		while FLAG_EVAL: (true)
-		{
-			switch (c)
-			{
-				case '0': this.flags.zeropad = true;
-				case '-': this.flags.left = true;
-				case '+': this.flags.plus = true;
-				case ' ': this.flags.space = true;
-				case '#': this.flags.hash = true;
-				default: break FLAG_EVAL;
-			}
-			if (++i >= format_len) return PrintFault.INVALID_FORMAT_STRING!;
-			c = format[i];
-		}
-		// evaluate width field
-		int w = printf_parse_format_field(variants.ptr, variants.len, &variant_index, format.ptr, format.len, &i)?;
-		c = format[i];
-		if (w < 0)
-		{
-			this.flags.left = true;
-			w = -w;
-		}
-		this.width = w;
-		// evaluate precision field
-		this.prec = 0;
-		if (c == '.')
-		{
-			this.flags.precision = true;
-			if (++i >= format_len) return PrintFault.INVALID_FORMAT_STRING!;
-			int prec = printf_parse_format_field(variants.ptr, variants.len, &variant_index, format.ptr, format.len, &i)?;
-			this.prec = prec < 0 ? 0 : prec;
-			c = format[i];
-		}
-
-		// evaluate specifier
-		uint base = 0;
-		if (variant_index >= variants.len) return PrintFault.MISSING_ARG!;
-		variant current = variants[variant_index++];
-		switch (c)
-		{
-			case 'd':
-				base = 10;
-				this.flags.hash = false;
-			case 'X' :
-				this.flags.uppercase = true;
-				nextcase;
-			case 'x' :
-				base = 16;
-			case 'O':
-				this.flags.uppercase = true;
-				nextcase;
-			case 'o' :
-				base = 8;
-			case 'B':
-				this.flags.uppercase = true;
-				nextcase;
-			case 'b' :
-				base = 2;
-			case 'A':
-				this.flags.uppercase = true;
-				nextcase;
-			case 'a':
-				this.atoa(float_from_variant(current)!!)?;
-				continue;
-		    case 'F' :
-		        this.flags.uppercase = true;
-		        nextcase;
-		    case 'f':
-		        this.ftoa(float_from_variant(current)!!)?;
-				continue;
-			case 'E':
-		        this.flags.uppercase = true;
-		        nextcase;
-            case 'e':
-                this.etoa(float_from_variant(current)!!)?;
-				continue;
-			case 'G':
-				this.flags.uppercase = true;
-				nextcase;
-			case 'g':
-				this.gtoa(float_from_variant(current)!!)?;
-				continue;
-			case 'c':
-				this.out_char(current)?;
-				continue;
-			case 's':
-				this.out_str(current)?;
-				continue;
-			case 'p':
-				this.flags.zeropad = true;
-				this.flags.hash = true;
-				base = 16;
-			default:
-				return PrintFault.INVALID_FORMAT_STRING!;
-		}
-		if (base != 10)
-		{
-			this.flags.plus = false;
-			this.flags.space = false;
-		}
-		// ignore '0' flag when precision is given
-		if (this.flags.precision) this.flags.zeropad = false;
-
-		bool is_neg;
-		uint128 v = int_from_variant(current, &is_neg)!!;
-
-		this.ntoa(v, is_neg, base)?;
-	}
-	// termination
-	//	out((char)0, buffer, idx < maxlen ? idx : maxlen - 1U, maxlen);
-
-	// return written chars without terminating \0
-	return this.idx;
-}
-
-typedef StringFunctionMap @private = HashMap<typeid, ToStringFunction>;
-typedef FormatterFunctionMap @private = HashMap<typeid, ToFormatFunction>;
-
-FormatterFunctionMap toformat_functions @private;
-StringFunctionMap tostring_functions @private;
--- a/lib/std/io/io_stream.c3
+++ b/lib/std/io/io_stream.c3
@@ -1,205 +0,0 @@
-module std::io;
-
-typedef CloseStreamFn = fn void!(Stream*);
-typedef FlushStreamFn = fn void!(Stream*);
-typedef SeekStreamFn = fn usz!(Stream*, isz offset, Seek seek);
-typedef LenStreamFn = fn usz(Stream*);
-typedef AvailableStreamFn = fn usz(Stream*);
-typedef ReadStreamFn = fn usz!(Stream*, char[] bytes);
-typedef ReadFromStreamFn = fn usz!(Stream*, Stream*);
-typedef ReadByteStreamFn = fn char!(Stream*);
-typedef PushbackByteStreamFn = fn void!(Stream*);
-typedef WriteStreamFn = fn usz!(Stream*, char[] bytes);
-typedef WriteToStreamFn = fn usz!(Stream*, Stream* out);
-typedef WriteByteStreamFn = fn void!(Stream*, char c);
-typedef DestroyStreamFn = fn void!(Stream*);
-
-struct StreamInterface
-{
-	CloseStreamFn close_fn;
-	FlushStreamFn flush_fn;
-	SeekStreamFn seek_fn;
-	LenStreamFn len_fn;
-	AvailableStreamFn available_fn;
-	ReadStreamFn read_fn;
-	ReadFromStreamFn read_stream_fn;
-	ReadByteStreamFn read_byte_fn;
-	PushbackByteStreamFn pushback_byte_fn;
-	WriteStreamFn write_fn;
-	WriteToStreamFn write_stream_fn;
-	WriteByteStreamFn write_byte_fn;
-	DestroyStreamFn destroy_fn;
-}
-
-struct Stream
-{
-	StreamInterface *fns;
-	void* data;
-}
-
-fn bool Stream.supports_seek(Stream* s) @inline => (bool)s.fns.seek_fn;
-fn bool Stream.supports_available(Stream* s) @inline => s.fns.available_fn || s.fns.seek_fn;
-fn bool Stream.supports_len(Stream* s) @inline => s.fns.len_fn || s.fns.seek_fn;
-fn bool Stream.supports_read(Stream* s) @inline => s.fns.read_fn || s.fns.read_byte_fn;
-fn bool Stream.supports_read_from(Stream* s) @inline => (bool)s.fns.read_stream_fn;
-fn bool Stream.supports_write_to(Stream* s) @inline => (bool)s.fns.write_stream_fn;
-fn bool Stream.supports_pushback_byte(Stream* s) @inline => s.fns.pushback_byte_fn || s.fns.seek_fn;
-fn bool Stream.supports_write(Stream* s) @inline => s.fns.write_fn || s.fns.write_byte_fn;
-
-fn void! Stream.destroy(Stream* s) @inline @maydiscard
-{
-	if (s.fns.destroy_fn) return s.fns.destroy_fn(s);
-	return s.close();
-}
-
-fn void! Stream.close(Stream* s) @inline @maydiscard
-{
-	if (CloseStreamFn func = s.fns.close_fn) return func(s);
-}
-
-fn usz! Stream.seek(Stream* s, isz offset, Seek seek) @inline
-{
-	if (SeekStreamFn func = s.fns.seek_fn) return func(s, offset, seek);
-	return IoError.NOT_SEEKABLE!;
-}
-
-fn usz! Stream.available(Stream* s) @inline
-{
-	if (AvailableStreamFn func = s.fns.available_fn) return func(s);
-	if (SeekStreamFn func = s.fns.seek_fn)
-	{
-		usz curr = func(s, 0, Seek.CURSOR)?;
-		usz len = func(s, 0, Seek.END)?;
-		func(s, curr, Seek.SET)?;
-		return len - curr;
-	}
-	return IoError.NOT_SEEKABLE!;
-}
-
-fn usz! Stream.read(Stream* s, char[] buffer)
-{
-	if (ReadStreamFn func = s.fns.read_fn) return func(s, buffer);
-	if (ReadByteStreamFn func = s.fns.read_byte_fn)
-	{
-		usz len = 0;
-		foreach (&cptr : buffer)
-		{
-			char! c = func(s);
-			if (catch err = c)
-			{
-				case IoError.EOF: return len;
-				default: return err!;
-			}
-			*cptr = c;
-			len++;
-		}
-	}
-	return IoError.UNSUPPORTED_OPERATION!;
-}
-
-fn char! Stream.read_byte(Stream* s) @inline
-{
-	if (ReadByteStreamFn func = s.fns.read_byte_fn) return func(s);
-	return IoError.UNSUPPORTED_OPERATION!;
-}
-
-fn usz! Stream.write(Stream* s, char[] bytes) @inline
-{
-	if (WriteStreamFn func = s.fns.write_fn) return func(s, bytes);
-	if (WriteByteStreamFn func = s.fns.write_byte_fn)
-	{
-		foreach (c : bytes) func(s, c)?;
-		return bytes.len;
-	}
-	return IoError.UNSUPPORTED_OPERATION!;
-}
-
-fn void! Stream.write_byte(Stream* s, char b) @inline
-{
-	if (WriteByteStreamFn func = s.fns.write_byte_fn) return func(s, b);
-	return IoError.UNSUPPORTED_OPERATION!;
-}
-
-fn usz! Stream.write_to(Stream* s, Stream* to) @inline
-{
-	if (WriteToStreamFn func = s.fns.write_stream_fn) return func(s, to);
-	return IoError.UNSUPPORTED_OPERATION!;
-}
-
-fn usz! Stream.read_from(Stream* s, Stream* from) @inline
-{
-	if (ReadFromStreamFn func = s.fns.read_stream_fn) return func(s, from);
-	return IoError.UNSUPPORTED_OPERATION!;
-}
-
-fn void! Stream.flush(Stream* s) @inline @maydiscard
-{
-	if (FlushStreamFn func = s.fns.flush_fn) return func(s);
-	return IoError.UNSUPPORTED_OPERATION!;
-}
-
-fn usz! Stream.len(Stream* s) @inline
-{
-	if (LenStreamFn func = s.fns.len_fn) return func(s);
-	if (SeekStreamFn func = s.fns.seek_fn)
-	{
-		usz curr = func(s, 0, Seek.CURSOR)?;
-		usz len = func(s, 0, Seek.END)?;
-		func(s, curr, Seek.SET)?;
-		return len;
-	}
-	return IoError.NOT_SEEKABLE!;
-}
-
-fn void! Stream.pushback_byte(Stream* s) @inline
-{
-	if (PushbackByteStreamFn func = s.fns.pushback_byte_fn) return func(s);
-	if (SeekStreamFn func = s.fns.seek_fn)
-	{
-		func(s, -1, CURSOR)?;
-		return;
-	}
-	return IoError.UNSUPPORTED_OPERATION!;
-}
-
-fn void! Stream.write_string(Stream* s, String str) @inline => (void)(s.write((char[])str)?);
-
-fn usz! Stream.copy_to(Stream* s, Stream* dst, char[] buffer = {})
-{
-	if (buffer.len) return copy_through_buffer(s, dst, buffer);
-	if (WriteToStreamFn func = s.fns.write_stream_fn) return func(s, dst);
-	if (ReadFromStreamFn func = dst.fns.read_stream_fn) return func(dst, s);
-$switch (env::MEMORY_ENV)
-$case NORMAL:
-	@pool()
-	{
-		return copy_through_buffer(s, dst, tmalloc(char, 4096));
-	};
-$case SMALL:
-	@pool()
-	{
-		return copy_through_buffer(s, dst, tmalloc(char, 1024));
-	};
-$case TINY:
-$case NONE:
-	return copy_through_buffer(s, dst, &&(char[256]{}));
-$endswitch
-}
-
-macro usz! copy_through_buffer(Stream* s, Stream* dst, char[] buffer) @local
-{
-	usz total_copied;
-	while (true)
-	{
-		usz! len = s.read(buffer);
-		if (catch err = len)
-		{
-			case IoError.EOF: return total_copied;
-			default: return err!;
-		}
-		if (!len) return total_copied;
-		usz written = dst.write(buffer[:len])?;
-		total_copied += len;
-		if (written != len) return IoError.INCOMPLETE_WRITE!;
-	}
-}
--- a/lib/std/io/os/chdir.c3
+++ b/lib/std/io/os/chdir.c3
@@ -1,43 +1,30 @@
 module std::io::os;
 import libc;

-
-$switch
-	$case !env::COMPILER_LIBC_AVAILABLE:
-
-fn void! native_chdir(Path path)
-{
-	unreachable("'getcwd' not available");
-}
-
-	$case env::os_is_win32():
-
 macro void! native_chdir(Path path)
 {
-	@pool()
-	{
-		 if (files::win32_SetCurrentDirectoryW(path.as_str().to_temp_utf16()!!)) return;
-	};
-	return IoError.GENERAL_ERROR!;
+	$switch
+		$case env::POSIX:
+			if (posix::chdir(path.as_zstr()))
+			{
+				switch (libc::errno())
+				{
+					case errno::EACCES: return IoError.NO_PERMISSION?;
+					case errno::ENAMETOOLONG: return IoError.NAME_TOO_LONG?;
+					case errno::ENOTDIR: return IoError.FILE_NOT_DIR?;
+					case errno::ENOENT: return IoError.FILE_NOT_FOUND?;
+					case errno::ELOOP: return IoError.SYMLINK_FAILED?;
+					default: return IoError.GENERAL_ERROR?;
+				}
+			}
+		$case env::WIN32:
+			@pool()
+			{
+				// TODO improve with better error handling.
+				if (win32::setCurrentDirectoryW(path.str_view().to_temp_utf16()!!)) return;
+			};
+			return IoError.GENERAL_ERROR?;
+		$default:
+			return IoError.UNSUPPORTED_OPERATION?;
+	$endswitch
 }
-
-	$default:
-
-extern fn int _chdir(ZString) @extern("chdir");
-macro void! native_chdir(Path p)
-{
-	if (_chdir((ZString)p.as_str()))
-	{
-		switch (libc::errno())
-		{
-			case errno::EACCES: return IoError.NO_PERMISSION!;
-			case errno::ENAMETOOLONG: return IoError.NAME_TOO_LONG!;
-			case errno::ENOTDIR: return IoError.FILE_NOT_DIR!;
-			case errno::ENOENT: return IoError.FILE_NOT_FOUND!;
-			case errno::ELOOP: return IoError.SYMLINK_FAILED!;
-			default: return IoError.GENERAL_ERROR!;
-		}
-	}
-}
-
-$endswitch
--- a/lib/std/io/os/file.c3
+++ b/lib/std/io/os/file.c3
@@ -1,187 +0,0 @@
-module std::io::os;
-import libc;
-
-typedef FopenFn = fn void*!(String, String);
-typedef FreopenFn = fn void*!(void*, String, String);
-typedef FcloseFn = fn void!(void*);
-typedef FseekFn = fn void!(void*, isz, Seek);
-typedef FtellFn = fn usz!(void*);
-typedef FwriteFn = fn usz!(void*, char[] buffer);
-typedef FreadFn = fn usz!(void*, char[] buffer);
-
-$if (!$defined(native_fopen_fn))
-FopenFn native_fopen_fn @weak;
-$endif
-$if (!$defined(native_fclose_fn))
-FcloseFn native_fclose_fn @weak;
-$endif
-$if (!$defined(native_freopen_fn))
-FreopenFn native_freopen_fn @weak;
-$endif
-$if (!$defined(native_fseek_fn))
-FseekFn native_fseek_fn @weak;
-$endif
-$if (!$defined(native_ftell_fn))
-FtellFn native_ftell_fn @weak;
-$endif
-$if (!$defined(native_fwrite_fn))
-FwriteFn native_fwrite_fn @weak;
-$endif
-$if (!$defined(native_fread_fn))
-FreadFn native_fread_fn @weak;
-$endif
-
-
-/**
- * @require mode.len > 0
- * @require filename.len > 0
- **/
-fn void*! native_fopen(String filename, String mode) @inline
-{
-$if (!env::COMPILER_LIBC_AVAILABLE)
-		if (native_fopen_fn) return native_fopen_fn(filename, mode);
-		unreachable("Tried to call fopen without support.");
-$else
-	@pool()
-	{
-	$if (env::os_is_win32())
-		void* file = (CFile)_wfopen(filename.to_temp_utf16(), filename.to_temp_utf16())?;
-	$else
-		void* file = libc::fopen(filename.zstr_tcopy(), mode.zstr_tcopy());
-	$endif
-		return file ?: file_open_errno()!;
-	};
-$endif
-}
-
-/**
- * @require mode.len > 0
- * @require filename.len > 0
- **/
-fn void*! native_freopen(void* file, String filename, String mode) @inline
-{
-$if (!env::COMPILER_LIBC_AVAILABLE)
-		if (native_freopen_fn) return native_freopen_fn(file, filename, mode);
-		unreachable("Tried to call freopen without support.");
-$else
-	@pool()
-	{
-	$if (env::os_is_win32())
-		file = _wfreopen(filename.to_temp_utf16(), mode.to_temp_utf16(), file)?;
-	$else
-		file = libc::freopen(filename.zstr_tcopy(), mode.zstr_tcopy(), file);
-	$endif
-		return file ?: file_open_errno()!;
-	};
-$endif
-}
-
-fn void! native_fseek(void* file, isz offset, Seek seek_mode) @inline
-{
-$if (!env::COMPILER_LIBC_AVAILABLE)
-	if (native_fseek_fn) return native_fseek_fn(file, offset, seek_mode);
-	unreachable("Tried to call fseek without support.");
-$else
-	$if (env::os_is_win32())
-		bool success = _fseeki64(file, (long)offset, (int)seek_mode) == 0;
-	$else
-		bool success = libc::fseek(file, (SeekIndex)offset, (CInt)seek_mode) == 0;
-	$endif
-		if (!success) return file_seek_errno()!;
-$endif
-}
-
-fn usz! native_ftell(CFile file) @inline
-{
-$if (!env::COMPILER_LIBC_AVAILABLE)
-	if (native_ftell_fn) return native_ftell_fn(file);
-	unreachable("Tried to call ftell without support.");
-$else
-	$if (env::os_is_win32())
-		long index = _ftelli64(file);
-		return index >= 0 ? index : file_seek_errno()!;
-	$else
-		SeekIndex index = libc::ftell(file);
-		return index >= 0 ? index : file_seek_errno()!;
-	$endif
-$endif
-}
-
-fn usz! native_fwrite(CFile file, char[] buffer) @inline
-{
-$if (!env::COMPILER_LIBC_AVAILABLE)
-	if (native_fwrite_fn) return native_fwrite_fn(file, buffer);
-	unreachable("Tried to call fwrite without support.");
-$else
-    return libc::fwrite(buffer.ptr, 1, buffer.len, file);
-$endif
-}
-
-fn usz! native_fread(CFile file, char[] buffer) @inline
-{
-$if (!env::COMPILER_LIBC_AVAILABLE)
-	if (native_fread_fn) return native_fread_fn(file, buffer);
-	unreachable("Tried to call fread without support.");
-$else
-    return libc::fread(buffer.ptr, 1, buffer.len, file);
-$endif
-}
-
-macro anyerr file_open_errno() @local
-{
-	switch (libc::errno())
-	{
-	    case errno::EACCES: return IoError.NO_PERMISSION;
-	    case errno::EDQUOT: return IoError.OUT_OF_SPACE;
-	    case errno::EBADF: return IoError.FILE_NOT_VALID;
-	    case errno::EEXIST: return IoError.ALREADY_EXISTS;
-	    case errno::EINTR: return IoError.INTERRUPTED;
-	    case errno::EFAULT: return IoError.GENERAL_ERROR;
-	    case errno::EISDIR: return IoError.FILE_IS_DIR;
-	    case errno::ELOOP: return IoError.SYMLINK_FAILED;
-	    case errno::EMFILE: return IoError.TOO_MANY_DESCRIPTORS;
-	    case errno::ENAMETOOLONG: return IoError.NAME_TOO_LONG;
-	    case errno::ENFILE: return IoError.OUT_OF_SPACE;
-	    case errno::ENOTDIR: return IoError.FILE_NOT_DIR;
-		case errno::ENOENT: return IoError.FILE_NOT_FOUND;
-	    case errno::ENOSPC: return IoError.OUT_OF_SPACE;
-		case errno::ENXIO: return IoError.FILE_NOT_FOUND;
-		case errno::EOVERFLOW: return IoError.OVERFLOW;
-		case errno::EROFS: return IoError.READ_ONLY;
-		case errno::EOPNOTSUPP: return IoError.UNSUPPORTED_OPERATION;
-	    case errno::EIO: return IoError.INCOMPLETE_WRITE;
-	    case errno::EWOULDBLOCK: return IoError.WOULD_BLOCK;
-	    default: return IoError.UNKNOWN_ERROR;
-	}
-}
-
-macro anyerr file_seek_errno() @local
-{
-	switch (libc::errno())
-	{
-		case errno::ESPIPE: return IoError.FILE_IS_PIPE;
-		case errno::EPIPE: return IoError.FILE_IS_PIPE;
-		case errno::EOVERFLOW: return IoError.OVERFLOW;
-	    case errno::ENXIO: return IoError.FILE_NOT_FOUND;
-	    case errno::ENOSPC: return IoError.OUT_OF_SPACE;
-        case errno::EIO: return IoError.INCOMPLETE_WRITE;
-		case errno::EINVAL: return IoError.INVALID_POSITION;
-	    case errno::EINTR: return IoError.INTERRUPTED;
-	    case errno::EFBIG: return IoError.OUT_OF_SPACE;
-	    case errno::EBADF: return IoError.FILE_NOT_VALID;
-	    case errno::EAGAIN: return IoError.WOULD_BLOCK;
-	    default: return IoError.UNKNOWN_ERROR;
-	}
-}
-
-// Win functions
-$if (env::os_is_win32())
-extern fn void* _wfopen(Char16*, Char16*) @local;
-extern fn void* _wfreopen(Char16*, Char16*, CFile) @local;
-extern fn int _fseeki64(CFile, long, int) @local;
-extern fn long _ftelli64(CFile) @local;
-$endif
-
-$if (env::os_is_posix())
-extern fn CInt access(ZString path, CInt mode);
-$endif
--- a/lib/std/io/os/file_libc.c3
+++ b/lib/std/io/os/file_libc.c3
@@ -0,0 +1,129 @@
+module std::io::os @if(env::LIBC);
+import libc;
+
+/**
+ * @require mode.len > 0
+ * @require filename.len > 0
+ **/
+fn void*! native_fopen(String filename, String mode) @inline
+{
+	@pool()
+	{
+		$if env::WIN32:
+			void* file = libc::_wfopen(filename.to_temp_wstring(), mode.to_temp_wstring())!;
+		$else
+			void* file = libc::fopen(filename.zstr_tcopy(), mode.zstr_tcopy());
+		$endif
+			return file ?: file_open_errno()?;
+	};
+}
+
+fn void! native_remove(String filename)
+{
+	@pool()
+	{
+		$if env::WIN32:
+			CInt result = libc::_wremove(filename.to_temp_wstring())!;
+		$else
+			CInt result = libc::remove(filename.zstr_tcopy());
+		$endif
+		if (result)
+		{
+			switch (libc::errno())
+			{
+				case errno::ENOENT:
+					return IoError.FILE_NOT_FOUND?;
+				case errno::EACCES:
+				default:
+					return IoError.FILE_CANNOT_DELETE?;
+			}
+		}
+	};
+}
+
+/**
+ * @require mode.len > 0
+ * @require filename.len > 0
+ **/
+fn void*! native_freopen(void* file, String filename, String mode) @inline
+{
+	@pool()
+	{
+		$if env::WIN32:
+			file = libc::_wfreopen(filename.to_temp_wstring(), mode.to_temp_wstring(), file)!;
+		$else
+			file = libc::freopen(filename.zstr_tcopy(), mode.zstr_tcopy(), file);
+		$endif
+			return file ?: file_open_errno()?;
+	};
+}
+
+fn void! native_fseek(void* file, isz offset, Seek seek_mode) @inline
+{
+	if (libc::fseek(file, (SeekIndex)offset, (CInt)seek_mode)) return file_seek_errno()?;
+}
+
+
+fn usz! native_ftell(CFile file) @inline
+{
+	long index = libc::ftell(file);
+	return index >= 0 ? (usz)index : file_seek_errno()?;
+}
+
+fn usz! native_fwrite(CFile file, char[] buffer) @inline
+{
+	return libc::fwrite(buffer.ptr, 1, buffer.len, file);
+}
+
+fn usz! native_fread(CFile file, char[] buffer) @inline
+{
+	return libc::fread(buffer.ptr, 1, buffer.len, file);
+}
+
+macro anyfault file_open_errno() @local
+{
+	switch (libc::errno())
+	{
+		case errno::EACCES: return IoError.NO_PERMISSION;
+		case errno::EDQUOT: return IoError.OUT_OF_SPACE;
+		case errno::EBADF: return IoError.FILE_NOT_VALID;
+		case errno::EEXIST: return IoError.ALREADY_EXISTS;
+		case errno::EINTR: return IoError.INTERRUPTED;
+		case errno::EFAULT: return IoError.GENERAL_ERROR;
+		case errno::EISDIR: return IoError.FILE_IS_DIR;
+		case errno::ELOOP: return IoError.SYMLINK_FAILED;
+		case errno::EMFILE: return IoError.TOO_MANY_DESCRIPTORS;
+		case errno::ENAMETOOLONG: return IoError.NAME_TOO_LONG;
+		case errno::ENFILE: return IoError.OUT_OF_SPACE;
+		case errno::ENOTDIR: return IoError.FILE_NOT_DIR;
+		case errno::ENOENT: return IoError.FILE_NOT_FOUND;
+		case errno::ENOSPC: return IoError.OUT_OF_SPACE;
+		case errno::ENXIO: return IoError.FILE_NOT_FOUND;
+		case errno::EOVERFLOW: return IoError.OVERFLOW;
+		case errno::EROFS: return IoError.READ_ONLY;
+		case errno::EOPNOTSUPP: return IoError.UNSUPPORTED_OPERATION;
+		case errno::EIO: return IoError.INCOMPLETE_WRITE;
+		case errno::EWOULDBLOCK: return IoError.WOULD_BLOCK;
+		default: return IoError.UNKNOWN_ERROR;
+	}
+}
+
+macro anyfault file_seek_errno() @local
+{
+	switch (libc::errno())
+	{
+		case errno::ESPIPE: return IoError.FILE_IS_PIPE;
+		case errno::EPIPE: return IoError.FILE_IS_PIPE;
+		case errno::EOVERFLOW: return IoError.OVERFLOW;
+		case errno::ENXIO: return IoError.FILE_NOT_FOUND;
+		case errno::ENOSPC: return IoError.OUT_OF_SPACE;
+		case errno::EIO: return IoError.INCOMPLETE_WRITE;
+		case errno::EINVAL: return IoError.INVALID_POSITION;
+		case errno::EINTR: return IoError.INTERRUPTED;
+		case errno::EFBIG: return IoError.OUT_OF_SPACE;
+		case errno::EBADF: return IoError.FILE_NOT_VALID;
+		case errno::EAGAIN: return IoError.WOULD_BLOCK;
+		default: return IoError.UNKNOWN_ERROR;
+	}
+}
+
--- a/lib/std/io/os/file_nolibc.c3
+++ b/lib/std/io/os/file_nolibc.c3
@@ -0,0 +1,75 @@
+module std::io::os @if(env::NO_LIBC);
+import libc;
+
+def FopenFn = fn void*!(String, String);
+def FreopenFn = fn void*!(void*, String, String);
+def FcloseFn = fn void!(void*);
+def FseekFn = fn void!(void*, isz, Seek);
+def FtellFn = fn usz!(void*);
+def FwriteFn = fn usz!(void*, char[] buffer);
+def FreadFn = fn usz!(void*, char[] buffer);
+def RemoveFn = fn void!(String);
+
+FopenFn native_fopen_fn @weak @if(!$defined(native_fopen_fn));
+FcloseFn native_fclose_fn @weak @if(!$defined(native_fclose_fn));
+FreopenFn native_freopen_fn @weak @if(!$defined(native_freopen_fn));
+FseekFn native_fseek_fn @weak @if(!$defined(native_fseek_fn));
+FtellFn native_ftell_fn @weak @if(!$defined(native_ftell_fn));
+FwriteFn native_fwrite_fn @weak @if(!$defined(native_fwrite_fn));
+FreadFn native_fread_fn @weak @if(!$defined(native_fread_fn));
+RemoveFn native_remove_fn @weak @if(!$defined(native_remove_fn));
+
+/**
+ * @require mode.len > 0
+ * @require filename.len > 0
+ **/
+fn void*! native_fopen(String filename, String mode) @inline
+{
+	if (native_fopen_fn) return native_fopen_fn(filename, mode);
+	return IoError.UNSUPPORTED_OPERATION?;
+}
+
+/**
+ * Delete a file.
+ *
+ * @require filename.len > 0
+ **/
+fn void! native_remove(String filename) @inline
+{
+	if (native_remove_fn) return native_remove_fn(filename);
+	return IoError.UNSUPPORTED_OPERATION?;
+}
+
+/**
+ * @require mode.len > 0
+ * @require filename.len > 0
+ **/
+fn void*! native_freopen(void* file, String filename, String mode) @inline
+{
+	if (native_freopen_fn) return native_freopen_fn(file, filename, mode);
+	return IoError.UNSUPPORTED_OPERATION?;
+}
+
+fn void! native_fseek(void* file, isz offset, Seek seek_mode) @inline
+{
+	if (native_fseek_fn) return native_fseek_fn(file, offset, seek_mode);
+	return IoError.UNSUPPORTED_OPERATION?;
+}
+
+fn usz! native_ftell(CFile file) @inline
+{
+	if (native_ftell_fn) return native_ftell_fn(file);
+	return IoError.UNSUPPORTED_OPERATION?;
+}
+
+fn usz! native_fwrite(CFile file, char[] buffer) @inline
+{
+	if (native_fwrite_fn) return native_fwrite_fn(file, buffer);
+	return IoError.UNSUPPORTED_OPERATION?;
+}
+
+fn usz! native_fread(CFile file, char[] buffer) @inline
+{
+	if (native_fread_fn) return native_fread_fn(file, buffer);
+	return IoError.UNSUPPORTED_OPERATION?;
+}
--- a/lib/std/io/os/fileinfo.c3
+++ b/lib/std/io/os/fileinfo.c3
@@ -0,0 +1,116 @@
+module std::io::os;
+import libc;
+
+fn void! native_stat(Stat* stat, String path) @if(env::DARWIN || env::LINUX)
+{
+	@pool()
+	{
+		$if env::DARWIN || env::LINUX:
+			int res = libc::stat(path.zstr_tcopy(), stat);
+		$else
+			unreachable("Stat unimplemented");
+			int res = 0;
+		$endif
+		if (res != 0)
+		{
+			switch (libc::errno())
+			{
+				case errno::EBADF:
+					return IoError.FILE_NOT_VALID?;
+				case errno::EFAULT:
+					unreachable("Invalid stat");
+				case errno::EIO:
+					return IoError.GENERAL_ERROR?;
+				case errno::EACCES:
+					return IoError.NO_PERMISSION?;
+				case errno::ELOOP:
+					return IoError.NO_PERMISSION?;
+				case errno::ENAMETOOLONG:
+					return IoError.NAME_TOO_LONG?;
+				case errno::ENOENT:
+					return IoError.FILE_NOT_FOUND?;
+				case errno::ENOTDIR:
+					return IoError.FILE_NOT_DIR?;
+				case errno::EOVERFLOW:
+					return IoError.GENERAL_ERROR?;
+				default:
+					return IoError.UNKNOWN_ERROR?;
+			}
+		}
+	};
+}
+
+fn usz! native_file_size(String path) @if(env::WIN32)
+{
+	@pool()
+	{
+		Win32_FILE_ATTRIBUTE_DATA data;
+		win32::getFileAttributesExW(path.to_temp_wstring()!, Win32_GET_FILEEX_INFO_LEVELS.STANDARD, &data);
+		Win32_LARGE_INTEGER size;
+		size.lowPart = data.nFileSizeLow;
+		size.highPart = data.nFileSizeHigh;
+		return (usz)size.quadPart;
+	};
+}
+
+fn usz! native_file_size(String path) @if(!env::WIN32 && !env::DARWIN)
+{
+	File f = file::open(path, "r")!;
+	defer (void)f.close();
+	return f.seek(0, Seek.END)!;
+}
+
+fn usz! native_file_size(String path) @if(env::DARWIN)
+{
+	Stat stat;
+	native_stat(&stat, path)!;
+	return stat.st_size;
+}
+
+fn bool native_file_or_dir_exists(String path)
+{
+	$switch
+		$case env::DARWIN:
+		$case env::LINUX:
+			Stat stat;
+			return @ok(native_stat(&stat, path));
+		$case env::WIN32:
+			@pool()
+			{
+				return (bool)win32::pathFileExistsW(path.to_temp_utf16()) ?? false;
+			};
+		$case env::POSIX:
+			@pool()
+			{
+				return posix::access(path.zstr_tcopy(), 0 /* F_OK */) != -1;
+			};
+		$default:
+			unreachable("Not supported");
+	$endswitch
+}
+
+fn bool native_is_file(String path)
+{
+	$switch
+		$case env::DARWIN:
+		$case env::LINUX:
+			Stat stat;
+			return @ok(native_stat(&stat, path)) && stat.st_mode & libc::S_IFREG;
+		$default:
+			File! f = file::open(path, "r");
+			defer (void)f.close();
+			return @ok(f);
+	$endswitch
+}
+
+fn bool native_is_dir(String path)
+{
+	$if env::DARWIN || env::LINUX:
+		Stat stat;
+		return @ok(native_stat(&stat, path)) && stat.st_mode & libc::S_IFDIR;
+	$else
+		return native_file_or_dir_exists(path) && !native_is_file(path);
+	$endif
+}
+
+
--- a/lib/std/io/os/fileinfo_darwin.c3
+++ b/lib/std/io/os/fileinfo_darwin.c3
@@ -1,102 +0,0 @@
-module std::io::file::os;
-import libc;
-
-$if (env::os_is_darwin())
-
-
-struct DarwinTimespec @private
-{
-	long tv_sec;
-	long tv_nsec;
-}
-struct Darwin64Stat @private
-{
-	int st_dev;
-	ushort st_mode;
-	ushort st_nlink;
-	ulong st_ino;
-	uint st_uid;
-	uint st_gid;
-	int st_rdev;
-	DarwinTimespec st_atimespec; // time of last access
-    DarwinTimespec st_mtimespec; // time of last data modification
-    DarwinTimespec st_ctimespec; // time of last status change
-    DarwinTimespec st_birthtimespec; // time of file creation(birth)
-    long st_size;
-    long st_blocks;
-    int st_blocksize;
-    uint st_flags;
-    uint st_gen;
-    int st_lspare;
-    long[2] st_qspare;
-}
-extern fn int _stat(ZString str, Darwin64Stat* stat) @extern("stat64");
-
-const S_IFMT   = 0o170000; // type of file mask
-const S_IFIFO  = 0o010000; // named pipe (fifo)
-const S_IFCHR  = 0o020000; // character special
-const S_IFDIR  = 0o040000; // directory
-const S_IFBLK  = 0o060000; // block special
-const S_IFREG  = 0o100000; // regular
-const S_IFLNK  = 0o120000; // symbolic link
-const S_IFSOCK = 0o140000; // socket
-
-fn usz! native_file_size(String path)
-{
-	Darwin64Stat stat;
-	read_stat(&stat, path)?;
-	return stat.st_size;
-}
-
-fn bool native_file_or_dir_exists(String path)
-{
-	Darwin64Stat stat;
-	return try? read_stat(&stat, path);
-}
-
-fn bool native_is_file(String path)
-{
-	Darwin64Stat stat;
-	return try? read_stat(&stat, path) && (stat.st_mode & S_IFREG);
-}
-
-fn bool native_is_dir(String path)
-{
-	Darwin64Stat stat;
-	return try? read_stat(&stat, path) && (stat.st_mode & S_IFDIR);
-}
-
-fn void! read_stat(Darwin64Stat* stat, String path) @local
-{
-	@pool()
-	{
-		int res = _stat(path.zstr_tcopy(), stat);
-		if (res != 0)
-		{
-			switch (libc::errno())
-			{
-				case errno::EBADF:
-					return IoError.FILE_NOT_VALID!;
-				case errno::EFAULT:
-					unreachable("Invalid stat");
-				case errno::EIO:
-					return IoError.GENERAL_ERROR!;
-				case errno::EACCES:
-					return IoError.NO_PERMISSION!;
-				case errno::ELOOP:
-					return IoError.NO_PERMISSION!;
-				case errno::ENAMETOOLONG:
-					return IoError.NAME_TOO_LONG!;
-				case errno::ENOENT:
-					return IoError.FILE_NOT_FOUND!;
-				case errno::ENOTDIR:
-					return IoError.FILE_NOT_DIR!;
-				case errno::EOVERFLOW:
-					return IoError.GENERAL_ERROR!;
-				default:
-					return IoError.UNKNOWN_ERROR!;
-			}
-		}
-	};
-}
-$endif
--- a/lib/std/io/os/fileinfo_other.c3
+++ b/lib/std/io/os/fileinfo_other.c3
@@ -1,143 +0,0 @@
-module std::io::file::os;
-
-// native_temp_directory, for non Win32
-$if (!env::os_is_win32())
-
-fn Path! native_temp_directory(Allocator* using = mem::heap())
-{
-	foreach (String env : { "TMPDIR", "TMP", "TEMP", "TEMPDIR" })
-	{
-		String tmpdir = env::get_var(env) ?? "";
-		if (tmpdir) return path::new(tmpdir, using);
-	}
-	return path::new("/tmp", using);
-}
-
-$if (env::COMPILER_LIBC_AVAILABLE)
-
-extern fn void* opendir(ZString);
-extern fn void closedir(void*);
-
-const DT_UNKNOWN =  0;
-const DT_FIFO    =  1;
-const DT_CHR     =  2;
-const DT_DIR     =  4;
-const DT_BLK     =  6;
-const DT_REG     =  8;
-const DT_LNK     = 10;
-const DT_SOCK    = 12;
-const DT_WHT     = 14;
-
-fn PathList! native_readdir(Path dir, bool no_dirs, bool no_symlinks, String mask, Allocator* using)
-{
-	PathList list;
-	list.init(.using = using);
-	void* directory = opendir(dir.as_str() ? dir.as_zstr() : (ZString)".");
-	defer if (directory) closedir(directory);
-	if (!directory) return (path::is_dir(dir) ? IoError.CANNOT_READ_DIR : IoError.FILE_NOT_DIR)!;
-	NativeDirentry* entry;
-	while ((entry = readdir(directory)))
-	{
-		String name = ((ZString)&entry.name).as_str();
-		if (!name || name == "." || name == "..") continue;
-		if (entry.type == DT_LNK && no_symlinks) continue;
-		if (entry.type == DT_DIR && no_dirs) continue;
-		Path path = path::new(name.copy(using), using)!!;
-		list.append(path);
-	}
-	return list;
-}
-
-$endif
-
-$endif
-
-$if (!env::os_is_darwin() && !env::os_is_win32())
-
-fn usz! native_file_size(String path)
-{
-	File f = file::open(path, "r")?;
-	defer (void)f.close();
-	return f.seek(0, Seek.END)?;
-}
-
-$if (env::os_is_posix() && env::COMPILER_LIBC_AVAILABLE)
-
-fn bool native_file_or_dir_exists(String path)
-{
-	@pool()
-	{
-		return os::access(path.zstr_tcopy(), 0 /* F_OK */) != -1;
-	};
-}
-
-fn bool native_is_file(String path)
-{
-	File! f = file::open(path, "r");
-	defer (void)f.close();
-	return try? f;
-}
-
-fn bool native_is_dir(String path)
-{
-	return native_file_or_dir_exists(path) && !native_is_file(path);
-}
-
-$else
-
-fn bool native_file_or_dir_exists(String path)
-{
-	unreachable("Tried to call file_or_dir_exists without support.");
-}
-
-fn bool native_is_dir(String path)
-{
-	unreachable("Tried to call is_dir without support.");
-}
-
-fn bool native_is_file(String path)
-{
-	unreachable("Tried to call is_file without support.");
-}
-
-$endif
-
-$endif
-
-$switch (env::OS_TYPE)
-$case IOS:
-$case MACOSX:
-$case TVOS:
-$case WATCHOS:
-extern fn NativeDirentry* readdir(void*) @extern("readdir$INODE64");
-struct NativeDirentry
-{
-	usz ino;
-	usz seekoff;
-	ushort reclen;
-	ushort namelen;
-	char type;
-	char[1024] name;
-}
-$case LINUX:
-extern fn NativeDirentry* readdir(void*);
-struct NativeDirentry
-{
-	usz ino;
-	isz seekoff;
-	ushort reclen;
-	char type;
-	char[*] name;
-}
-$default:
-// Fix this as we go along.
-extern fn NativeDirentry* readdir(void*);
-struct NativeDirentry
-{
-	usz ino;
-	isz seekoff;
-	ushort reclen;
-	char type;
-	char[*] name;
-}
-$endswitch
--- a/lib/std/io/os/fileinfo_win32.c3
+++ b/lib/std/io/os/fileinfo_win32.c3
@@ -1,63 +0,0 @@
-module std::io::file::os;
-import std::os::win32::files;
-
-$if (env::os_is_win32())
-
-fn usz! native_file_size(String path)
-{
-	@pool()
-	{
-		Char16[] path16 = path.to_temp_utf16()?;
-		Win32_FILE_ATTRIBUTE_DATA data;
-		files::win32_GetFileAttributesExW(path16, Win32_GET_FILEEX_INFO_LEVELS.STANDARD, &data);
-		Win32_LARGE_INTEGER size;
-		size.lowPart = data.nFileSizeLow;
-		size.highPart = data.nFileSizeHigh;
-		return (usz)size.quadPart;
-	};
-}
-
-fn bool native_file_or_dir_exists(String path)
-{
-	@pool()
-	{
-		return (bool)files::win32_PathFileExistsW(path.to_temp_utf16()) ?? false;
-	};
-}
-
-
-fn bool native_is_file(String path)
-{
-	File! f = file::open(path, "r");
-	defer (void)f.close();
-	return try? f;
-}
-
-fn bool native_is_dir(String path)
-{
-	return native_file_or_dir_exists(path) && !native_is_file(path);
-}
-
-fn Path! native_temp_directory(Allocator* using = mem::heap())
-{
-	@stack_mem(256; Allocator* mem)
-	{
-	    Win32_DWORD len = files::win32_GetTempPathW(0, null);
-		if (!len) return IoError.GENERAL_ERROR!;
-		Char16[] buff = malloc(Char16, len + 1, .using = mem);
-		if (!files::win32_GetTempPathW(len, buff)) return IoError.GENERAL_ERROR!;
-		return path::new(string::from_utf16(buff[:len], .using = mem), using);
-	};
-}
-
-/*
-
-	}else if(method == file_size_methods::get_attributes){
-		WIN32_FILE_ATTRIBUTE_DATA file_attr_data;
-		if(GetFileAttributesEx(path, GetFileExInfoStandard, &file_attr_data)){
-			file_size.LowPart = file_attr_data.nFileSizeLow;
-			file_size.HighPart = file_attr_data.nFileSizeHigh;
-		}
-	}
-*/
-$endif
--- a/lib/std/io/os/getcwd.c3
+++ b/lib/std/io/os/getcwd.c3
@@ -1,54 +1,41 @@
 module std::io::os;
 import libc;

-$switch
-$case !env::COMPILER_LIBC_AVAILABLE:
-
-fn String! getcwd(Allocator* using = mem::heap())
+macro String! getcwd(Allocator* allocator = mem::heap())
 {
-	unreachable("'getcwd' not available");
+	$switch
+		$case env::WIN32:
+			const DEFAULT_BUFFER = 256;
+			Char16[DEFAULT_BUFFER] buffer;
+			WString res = win32::_wgetcwd(&buffer, DEFAULT_BUFFER);
+			bool free = false;
+			defer if (free) libc::free(res);
+			if (!res)
+			{
+				if (libc::errno() != errno::ERANGE) return IoError.GENERAL_ERROR?;
+				res = win32::_wgetcwd(null, 0);
+				free = true;
+			}
+			Char16[] str16 = res[:win32::wcslen(res)];
+			return string::new_from_utf16(str16, allocator);
+
+		$case env::POSIX:
+			const usz DEFAULT_BUFFER = 256;
+			char[DEFAULT_BUFFER] buffer;
+			ZString res = posix::getcwd(&buffer, DEFAULT_BUFFER);
+			bool free = false;
+			if (!res)
+			{
+				// Improve error
+				if (libc::errno() != errno::ERANGE) return IoError.GENERAL_ERROR?;
+				res = posix::getcwd(null, 0);
+				free = true;
+			}
+			defer if (free) libc::free((void*)res);
+			return res.copy(allocator);
+
+		$default:
+			return IoError.UNSUPPORTED_OPERATION?;
+	$endswitch
 }

-$case env::os_is_win32():
-
-extern fn Char16* _wgetcwd(Char16* buffer, int maxlen);
-extern fn usz wcslen(Char16* str);
-
-macro String! getcwd(Allocator* using = mem::heap())
-{
-	const DEFAULT_BUFFER = 256;
-	Char16[DEFAULT_BUFFER] buffer;
-	Char16 *res = _wgetcwd(&buffer, DEFAULT_BUFFER);
-	bool free = false;
-	defer if (free) libc::free(res);
-	if (!res)
-	{
-	    if (libc::errno() != errno::ERANGE) return IoError.GENERAL_ERROR!;
-		res = _wgetcwd(null, 0);
-		free = true;
-	}
-	Char16[] str16 = res[:wcslen(res)];
-	return str::utf16to8(str16, using);
-}
-
-$default:
-
-extern fn ZString _getcwd(char* pwd, usz len) @extern("getcwd");
-macro String! getcwd(Allocator* using = mem::heap())
-{
-	const usz DEFAULT_BUFFER = 256;
-	char[DEFAULT_BUFFER] buffer;
-	ZString res = _getcwd(&buffer, DEFAULT_BUFFER);
-	bool free = false;
-	if (!res)
-	{
-		// Improve error
-		if (libc::errno() != errno::ERANGE) return IoError.GENERAL_ERROR!;
-		res = _getcwd(null, 0);
-		free = true;
-	}
-	defer if (free) libc::free((void*)res);
-	return res.copy(using);
-}
-
-$endswitch
--- a/lib/std/io/os/ls.c3
+++ b/lib/std/io/os/ls.c3
@@ -0,0 +1,49 @@
+module std::io::file::os @if(env::POSIX);
+
+fn PathList! native_ls(Path dir, bool no_dirs, bool no_symlinks, String mask, Allocator* allocator)
+{
+	PathList list;
+	list.init_new(.allocator = allocator);
+	DIRPtr directory = posix::opendir(dir.str_view() ? dir.as_zstr() : (ZString)".");
+	defer if (directory) posix::closedir(directory);
+	if (!directory) return (path::is_dir(dir) ? IoError.CANNOT_READ_DIR : IoError.FILE_NOT_DIR)?;
+	Posix_dirent* entry;
+	while ((entry = posix::readdir(directory)))
+	{
+		String name = ((ZString)&entry.name).str_view();
+		if (!name || name == "." || name == "..") continue;
+		if (entry.d_type == posix::DT_LNK && no_symlinks) continue;
+		if (entry.d_type == posix::DT_DIR && no_dirs) continue;
+		Path path = path::new(name, allocator)!!;
+		list.append(path);
+	}
+	return list;
+}
+
+module std::io::os @if(env::WIN32);
+
+fn PathList! native_ls(Path dir, bool no_dirs, bool no_symlinks, String mask, Allocator* allocator)
+{
+	PathList list;
+	list.init_new(.allocator = allocator);
+
+	@pool(allocator)
+	{
+		WString result = dir.str_view().tconcat(`\*`).to_temp_wstring()!!;
+		Win32_WIN32_FIND_DATAW find_data;
+		Win32_HANDLE find = win32::findFirstFileW(result, &find_data);
+		if (find == win32::INVALID_HANDLE_VALUE) return IoError.CANNOT_READ_DIR?;
+		defer win32::findClose(find);
+		do
+		{
+			if (no_dirs && (find_data.dwFileAttributes & win32::FILE_ATTRIBUTE_DIRECTORY)) continue;
+			@pool(allocator)
+			{
+				String filename = string::temp_from_wstring((WString)&find_data.cFileName)!;
+				if (filename == ".." || filename == ".") continue;
+				list.append(path::new(filename, allocator)!);
+			};
+		} while (win32::findNextFileW(find, &find_data));
+		return list;
+	};
+}
--- a/lib/std/io/os/mkdir.c3
+++ b/lib/std/io/os/mkdir.c3
@@ -0,0 +1,50 @@
+module std::io::os;
+import libc;
+import std::io::path;
+import std::os::win32;
+import std::os::posix;
+
+
+macro bool! native_mkdir(Path path, MkdirPermissions permissions)
+{
+	$switch
+		$case env::POSIX:
+			if (!posix::mkdir(path.as_zstr(), permissions == NORMAL ? 0o777 : 0o700)) return true;
+			switch (libc::errno())
+			{
+				case errno::EACCES:
+				case errno::EPERM:
+				case errno::EROFS:
+				case errno::EFAULT: return IoError.NO_PERMISSION?;
+				case errno::ENAMETOOLONG: return IoError.NAME_TOO_LONG?;
+				case errno::EDQUOT:
+				case errno::ENOSPC: return IoError.OUT_OF_SPACE?;
+				case errno::EISDIR:
+				case errno::EEXIST: return false;
+				case errno::ELOOP: return IoError.SYMLINK_FAILED?;
+				case errno::ENOTDIR: return IoError.FILE_NOT_FOUND?;
+				default: return IoError.GENERAL_ERROR?;
+			}
+		$case env::WIN32:
+			@pool()
+			{
+				// TODO security attributes
+				if (win32::createDirectoryW(path.str_view().to_temp_utf16()!!, null)) return true;
+				switch (win32::getLastError())
+				{
+					case win32::ERROR_ACCESS_DENIED:
+						return IoError.NO_PERMISSION?;
+					case win32::ERROR_DISK_FULL:
+						return IoError.OUT_OF_SPACE?;
+					case win32::ERROR_ALREADY_EXISTS:
+						return false;
+					case win32::ERROR_PATH_NOT_FOUND:
+						return IoError.FILE_NOT_FOUND?;
+					default:
+						return IoError.GENERAL_ERROR?;
+				}
+			};
+		$default:
+			return IoError.UNSUPPORTED_OPERATION?;
+	$endswitch
+}
--- a/lib/std/io/os/rmdir.c3
+++ b/lib/std/io/os/rmdir.c3
@@ -0,0 +1,48 @@
+module std::io::os;
+import libc;
+import std::io::path;
+import std::os::win32;
+import std::os::posix;
+
+macro bool! native_rmdir(Path path)
+{
+	$switch
+		$case env::POSIX:
+			if (!posix::rmdir(path.as_zstr())) return true;
+			switch (libc::errno())
+			{
+				case errno::EBUSY: return IoError.BUSY?;
+				case errno::EACCES:
+				case errno::EPERM:
+				case errno::EROFS:
+				case errno::EFAULT: return IoError.NO_PERMISSION?;
+				case errno::ENAMETOOLONG: return IoError.NAME_TOO_LONG?;
+				case errno::ENOTDIR:
+				case errno::ENOENT: return false;
+				case errno::ENOTEMPTY: return IoError.DIR_NOT_EMPTY?;
+				case errno::ELOOP: return IoError.SYMLINK_FAILED?;
+				default: return IoError.GENERAL_ERROR?;
+			}
+		$case env::WIN32:
+			@pool()
+			{
+				if (win32::removeDirectoryW(path.str_view().to_temp_utf16()!!)) return true;
+				switch (win32::getLastError())
+				{
+					case win32::ERROR_ACCESS_DENIED:
+						return IoError.NO_PERMISSION?;
+					case win32::ERROR_CURRENT_DIRECTORY:
+						return IoError.BUSY?;
+					case win32::ERROR_DIR_NOT_EMPTY:
+						return IoError.DIR_NOT_EMPTY?;
+					case win32::ERROR_DIRECTORY:
+					case win32::ERROR_PATH_NOT_FOUND:
+						return false;
+					default:
+						return IoError.GENERAL_ERROR?;
+				}
+			};
+		$default:
+			return IoError.UNSUPPORTED_OPERATION?;
+	$endswitch
+}
--- a/lib/std/io/os/rmtree.c3
+++ b/lib/std/io/os/rmtree.c3
@@ -0,0 +1,63 @@
+module std::io::file::os @if(env::POSIX);
+import libc;
+
+/**
+ * @require dir.str_view()
+ **/
+fn void! native_rmtree(Path dir)
+{
+	DIRPtr directory = posix::opendir(dir.as_zstr());
+	defer if (directory) posix::closedir(directory);
+	if (!directory) return path::is_dir(dir) ? IoError.CANNOT_READ_DIR? : IoError.FILE_NOT_DIR?;
+	Posix_dirent* entry;
+	while ((entry = posix::readdir(directory)))
+	{
+		@pool()
+		{
+			String name = ((ZString)&entry.name).str_view();
+			if (!name || name == "." || name == "..") continue;
+			Path new_path = dir.tappend(name)!;
+			if (entry.d_type == posix::DT_DIR)
+			{
+				native_rmtree(new_path)!;
+				continue;
+			}
+			if (libc::remove(new_path.as_zstr()))
+			{
+				// TODO improve
+				return IoError.GENERAL_ERROR?;
+			}
+		};
+	}
+	os::native_rmdir(dir)!;
+}
+
+module std::io::os @if(env::WIN32);
+
+fn void! native_rmtree(Path path)
+{
+	Win32_WIN32_FIND_DATAW find_data;
+	String s = path.str_view().tconcat("\\*");
+	Win32_HANDLE find = win32::findFirstFileW(s.to_temp_utf16(), &find_data)!;
+
+	if (find == win32::INVALID_HANDLE_VALUE) return IoError.CANNOT_READ_DIR?;
+	defer win32::findClose(find);
+	do
+	{
+		@pool()
+		{
+			String filename = string::new_from_wstring((WString)&find_data.cFileName, mem::temp())!;
+			if (filename == "." || filename == "..") continue;
+			Path file_path = path.tappend(filename)!;
+			if (find_data.dwFileAttributes & win32::FILE_ATTRIBUTE_DIRECTORY)
+			{
+				native_rmtree(file_path)!;
+			}
+			else
+			{
+				win32::deleteFileW(file_path.str_view().to_temp_wstring()!!);
+			}
+		};
+	} while (win32::findNextFileW(find, &find_data) != 0);
+	os::native_rmdir(path)!;
+}
--- a/lib/std/io/os/temp_directory.c3
+++ b/lib/std/io/os/temp_directory.c3
@@ -0,0 +1,30 @@
+module std::io::os @if(env::LIBC);
+
+fn Path! native_temp_directory(Allocator* allocator = mem::heap()) @if(!env::WIN32)
+{
+	foreach (String env : { "TMPDIR", "TMP", "TEMP", "TEMPDIR" })
+	{
+		String tmpdir = env::get_var(env) ?? "";
+		if (tmpdir) return path::new(tmpdir, allocator);
+	}
+	return path::new("/tmp", allocator);
+}
+
+fn Path! native_temp_directory(Allocator* allocator = mem::heap()) @if(env::WIN32)
+{
+	@pool(allocator)
+	{
+		Win32_DWORD len = win32::getTempPathW(0, null);
+		if (!len) return IoError.GENERAL_ERROR?;
+		Char16[] buff = mem::temp_array(Char16, len + (usz)1);
+		if (!win32::getTempPathW(len, buff)) return IoError.GENERAL_ERROR?;
+		return path::new(string::temp_from_utf16(buff[:len]), allocator);
+	};
+}
+
+module std::io::os @if(env::NO_LIBC);
+
+macro Path! native_temp_directory(Allocator* allocator = mem::heap())
+{
+	return IoError.UNSUPPORTED_OPERATION?;
+}
--- a/lib/std/io/path.c3
+++ b/lib/std/io/path.c3
@@ -1,12 +1,12 @@
 module std::io::path;
 import std::collections::list;

-const PathEnv DEFAULT_PATH_ENV = env::os_is_win32() ? PathEnv.WIN32 : PathEnv.POSIX;
+const PathEnv DEFAULT_PATH_ENV = env::WIN32 ? PathEnv.WIN32 : PathEnv.POSIX;
 const char PREFERRED_SEPARATOR_WIN32 = '\\';
 const char PREFERRED_SEPARATOR_POSIX = '/';
-const char PREFERRED_SEPARATOR = env::os_is_win32() ? PREFERRED_SEPARATOR_WIN32 : PREFERRED_SEPARATOR_POSIX;
+const char PREFERRED_SEPARATOR = env::WIN32 ? PREFERRED_SEPARATOR_WIN32 : PREFERRED_SEPARATOR_POSIX;

-typedef PathList = List<Path>;
+def PathList = List(<Path>);

 fault PathResult
 {
@@ -14,7 +14,7 @@ fault PathResult
 	NO_PARENT,
 }

-struct Path
+struct Path (Printable)
 {
 	String path_string;
 	PathEnv env;
@@ -26,22 +26,22 @@ enum PathEnv
 	POSIX
 }

-
-fn Path! getcwd(Allocator* using = mem::heap())
+fn Path! getcwd(Allocator* allocator = mem::heap())
 {
-	@stack_mem(256; Allocator* mem)
+	@pool(allocator)
 	{
-		return new(os::getcwd(mem), using);
+		return new(os::getcwd(mem::temp()), allocator);
 	};
 }

-fn bool is_dir(Path path) => os::native_is_dir(path.as_str());
-fn bool is_file(Path path) => os::native_is_file(path.as_str());
-fn usz! file_size(Path path) => os::native_file_size(path.as_str());
-fn bool exists(Path path) => os::native_file_or_dir_exists(path.as_str());
+fn bool is_dir(Path path) => os::native_is_dir(path.str_view());
+fn bool is_file(Path path) => os::native_is_file(path.str_view());
+fn usz! file_size(Path path) => os::native_file_size(path.str_view());
+fn bool exists(Path path) => os::native_file_or_dir_exists(path.str_view());
 fn Path! tgetcwd() => getcwd(mem::temp()) @inline;
 fn void! chdir(Path path) => os::native_chdir(path) @inline;
-fn Path! temp_directory(Allocator* using = mem::heap()) => os::native_temp_directory(using);
+fn Path! temp_directory(Allocator* allocator = mem::heap()) => os::native_temp_directory(allocator);
+fn void! delete(Path path) => os::native_remove(path.str_view()) @inline;

 macro bool is_separator(char c, PathEnv path_env = DEFAULT_PATH_ENV)
 {
@@ -58,94 +58,181 @@ macro bool is_win32_separator(char c)
 	return c == '/' || c == '\\';
 }

-fn Path! new(String path, Allocator* using = mem::heap(), PathEnv path_env = DEFAULT_PATH_ENV)
+fn PathList! ls(Path dir, bool no_dirs = false, bool no_symlinks = false, String mask = "", Allocator* allocator = mem::heap())
 {
-	return { normalize(path.copy(using), path_env), path_env };
+	$if $defined(os::native_ls):
+		return os::native_ls(dir, no_dirs, no_symlinks, mask, allocator);
+	$else
+		return IoError.UNSUPPORTED_OPERATION?;
+	$endif
 }

-fn Path! new_windows(String path, Allocator* using = mem::heap())
+enum MkdirPermissions
 {
-	return new(path, using, WIN32);
+	NORMAL,
+	USER_ONLY,
+	USER_AND_ADMIN
 }

-fn Path! new_posix(String path, Allocator* using = mem::heap())
+fn bool! mkdir(Path path, bool recursive = false, MkdirPermissions permissions = NORMAL)
 {
-	return new(path, using, POSIX);
+	if (!path.path_string.len) return PathResult.INVALID_PATH?;
+	if (is_dir(path)) return false;
+	if (exists(path)) return IoError.FILE_NOT_DIR?;
+
+	if (recursive)
+	{
+		if (try parent = path.parent()) mkdir(parent, true, permissions)!;
+	}
+	if (!is_dir(path.parent()) ?? false) return IoError.CANNOT_READ_DIR?;
+
+	return os::native_mkdir(path, permissions);
 }

-fn bool Path.equals(Path p1, Path p2)
+fn bool! rmdir(Path path)
 {
-	return p1.env == p2.env && p1.path_string == p2.path_string;
+	if (!path.path_string.len) return PathResult.INVALID_PATH?;
+	return os::native_rmdir(path);
+}
+
+fn void! rmtree(Path path)
+{
+	if (!path.path_string.len) return PathResult.INVALID_PATH?;
+	$if $defined(os::native_rmtree):
+		return os::native_rmtree(path);
+	$else
+		return IoError.UNSUPPORTED_OPERATION?;
+	$endif
+}
+
+fn Path! new(String path, Allocator* allocator = mem::heap(), PathEnv path_env = DEFAULT_PATH_ENV)
+{
+	return { normalize(path.copy(allocator), path_env), path_env };
+}
+
+fn Path! temp_new(String path, PathEnv path_env = DEFAULT_PATH_ENV)
+{
+	return new(path, mem::temp(), path_env);
+}
+
+fn Path! new_win32_wstring(WString path, Allocator* allocator = mem::heap())
+{
+	@pool(allocator)
+	{
+		return path::new(string::temp_from_wstring(path)!, .allocator = allocator);
+	};
+}
+
+fn Path! new_windows(String path, Allocator* allocator = mem::heap())
+{
+	return new(path, allocator, WIN32);
+}
+
+fn Path! new_posix(String path, Allocator* allocator = mem::heap())
+{
+	return new(path, allocator, POSIX);
+}
+
+fn bool Path.equals(self, Path p2)
+{
+	return self.env == p2.env && self.path_string == p2.path_string;
 }

 /**
 * Append the string to the current path.
 *
- * @param [in] path
 * @param [in] filename
- * @ensure return.path_string.len >= path.path_string.len
 **/
-fn Path! Path.append(Path path, String filename, Allocator* using = mem::heap())
+fn Path! Path.append(self, String filename, Allocator* allocator = mem::heap())
 {
-	if (!path.path_string.len) return new(filename, using, path.env)?;
-	assert(!is_separator(path.path_string[^1], path.env));
+	if (!self.path_string.len) return new(filename, allocator, self.env)!;
+	assert(!is_separator(self.path_string[^1], self.env));

-	@stack_mem(256; Allocator* mem)
+	@pool(allocator)
 	{
-		DString dstr = dstring::new_with_capacity(path.path_string.len + 1 + filename.len, .using = mem);
-		dstr.append(path.path_string);
+		DString dstr = dstring::temp_with_capacity(self.path_string.len + 1 + filename.len);
+		dstr.append(self.path_string);
 		dstr.append(PREFERRED_SEPARATOR);
 		dstr.append(filename);
-		return { normalize(dstr.copy_str(using), path.env), path.env };
+		return { normalize(dstr.copy_str(allocator), self.env), self.env };
 	};
 }

-fn Path! Path.tappend(Path path, String filename) => path.append(filename, mem::temp());
+fn Path! Path.tappend(self, String filename) => self.append(filename, mem::temp());

-fn usz Path.start_of_base_name(Path path) @local
+fn usz Path.start_of_base_name(self) @local
 {
-	String path_str = path.path_string;
+	String path_str = self.path_string;
 	if (!path_str.len) return 0;
-	if (path.env == PathEnv.WIN32)
+	if (self.env == PathEnv.WIN32)
 	{
-		return path_str.rindex_of(`\`) + 1 ?? volume_name_len(path_str, path.env)!!;
+		return path_str.rindex_of_char('\\') + 1 ?? volume_name_len(path_str, self.env)!!;
 	}
-	return path_str.rindex_of("/") + 1 ?? 0;
+	return path_str.rindex_of_char('/') + 1 ?? 0;
 }

-fn String Path.basename(Path path)
+fn bool! Path.is_absolute(self)
 {
-	usz basename_start = path.start_of_base_name();
-	String path_str = path.path_string;
+	String path_str = self.str_view();
+	if (!path_str.len) return false;
+	usz path_start = volume_name_len(path_str, self.env)!;
+	return path_start < path_str.len && is_separator(path_str[path_start], self.env);
+}
+
+fn Path! Path.absolute(self, Allocator* allocator = mem::heap())
+{
+	String path_str = self.str_view();
+	if (!path_str.len) path_str = ".";
+	if (path_str == ".")
+	{
+		String cwd = os::getcwd(mem::temp())!;
+		return new(cwd, allocator, self.env);
+	}
+	switch (self.env)
+	{
+		case WIN32:
+			usz path_start = volume_name_len(path_str, self.env)!;
+			if (path_start > 0) return self;
+		case POSIX:
+			if (path_str[0] == PREFERRED_SEPARATOR_POSIX) return self;
+	}
+	String cwd = os::getcwd(mem::temp())!;
+	return Path{ cwd, self.env }.append(path_str, allocator)!;
+}
+
+fn String Path.basename(self)
+{
+	usz basename_start = self.start_of_base_name();
+	String path_str = self.path_string;
 	if (basename_start == path_str.len) return "";
 	return path_str[basename_start..];
 }

-fn String Path.dirname(Path path)
+fn String Path.dirname(self)
 {
-	usz basename_start = path.start_of_base_name();
-	String path_str = path.path_string;
+	usz basename_start = self.start_of_base_name();
+	String path_str = self.path_string;
 	if (basename_start == 0) return "";
-	usz start = volume_name_len(path_str, path.env)!!;
+	usz start = volume_name_len(path_str, self.env)!!;
 	if (basename_start <= start + 1) return path_str[:basename_start];
 	return path_str[:basename_start - 1];
 }

-fn String! Path.extension(Path path)
+fn String! Path.extension(self)
 {
-	String basename = path.basename();
-	usz index = basename.rindex_of(".")?;
+	String basename = self.basename();
+	usz index = basename.rindex_of(".")!;
 	// Plain ".foo" does not have an
-	if (index == 0) return SearchResult.MISSING!;
+	if (index == 0) return SearchResult.MISSING?;
 	if (index == basename.len) return "";
 	return basename[index + 1..];
 }

-fn String Path.volume_name(Path path)
+fn String Path.volume_name(self)
 {
-	usz len = volume_name_len(path.as_str(), path.env)!!;
+	usz len = volume_name_len(self.str_view(), self.env)!!;
 	if (!len) return "";
-	return path.path_string[:len];
+	return self.path_string[:len];
 }

 fn usz! volume_name_len(String path, PathEnv path_env) @local
@@ -153,47 +240,47 @@ fn usz! volume_name_len(String path, PathEnv path_env) @local
 	usz len = path.len;
 	if (len < 2 || path_env != PathEnv.WIN32) return 0;
 	switch (path[0])
-    {
-    	case '\\':
-    	    // "\\" paths.. must be longer than 2
-    	    if (len == 2) return 0;
+	{
+		case '\\':
+			// "\\" paths.. must be longer than 2
+			if (len == 2) return 0;
 			int count = 1;
 			while (count < len && path[count] == '\\') count++;
 			// Not 2 => folded paths
 			if (count != 2) return 0;
 			// Check that we have a name followed by '/'
 			for (usz i = 2; i < len; i++)
-    		{
-    		    char c = path[i];
-    			if (is_win32_separator(c)) return i;
-    			if (is_reserved_win32_path_char(c)) return PathResult.INVALID_PATH!;
-    		}
-    		return PathResult.INVALID_PATH!;
-    	case 'A'..'Z':
-    	case 'a'..'z':
-    	    return path[1] == ':' ? 2 : 0;
-    	default:
-    	    return 0;
-    }
+			{
+				char c = path[i];
+				if (is_win32_separator(c)) return i;
+				if (is_reserved_win32_path_char(c)) return PathResult.INVALID_PATH?;
+			}
+			return PathResult.INVALID_PATH?;
+		case 'A'..'Z':
+		case 'a'..'z':
+			return path[1] == ':' ? 2 : 0;
+		default:
+			return 0;
+	}
 }

-fn Path! Path.parent(Path path)
+fn Path! Path.parent(self)
 {
-	if (path.path_string.len == 1 && is_separator(path.path_string[0], path.env)) return PathResult.NO_PARENT!;
-	foreach_r(i, c : path.path_string)
+	if (self.path_string.len == 1 && is_separator(self.path_string[0], self.env)) return PathResult.NO_PARENT?;
+	foreach_r(i, c : self.path_string)
 	{
-		if (is_separator(c, path.env))
+		if (is_separator(c, self.env))
 		{
-			return { path.path_string[:i], path.env };
+			return { self.path_string[:i], self.env };
 		}
 	}
-	return PathResult.NO_PARENT!;
+	return PathResult.NO_PARENT?;
 }

 fn String! normalize(String path_str, PathEnv path_env = DEFAULT_PATH_ENV)
 {
-	if (!path_str.len) return path_str;
-    usz path_start = volume_name_len(path_str, path_env)?;
+	if (!path_str.len) return "";
+	usz path_start = volume_name_len(path_str, path_env)!;
 	usz path_len = path_str.len;
 	if (path_start == path_len) return path_str;
 	char path_separator = path_env == PathEnv.WIN32 ? PREFERRED_SEPARATOR_WIN32 : PREFERRED_SEPARATOR_POSIX;
@@ -225,7 +312,7 @@ fn String! normalize(String path_str, PathEnv path_env = DEFAULT_PATH_ENV)

 		// The rest are names of the path elements, so check that the
 		// characters are valid.
-		if (is_reserved_path_char(c, path_env)) return PathResult.INVALID_PATH!;
+		if (is_reserved_path_char(c, path_env)) return PathResult.INVALID_PATH?;

 		// If we have '.' after a separator
 		if (c == '.' && previous_was_separator)
@@ -233,13 +320,20 @@ fn String! normalize(String path_str, PathEnv path_env = DEFAULT_PATH_ENV)
 			// Get the number of dots until next separator, expecting 1 or 2
 			bool is_last = i == path_len - 1;
 			int dots = 1;
-			if (!is_last && path_str[i + 1] == '.')
+			if (!is_last)
 			{
-				dots = 2;
-				is_last = i == path_len - 2;
-				if (!is_last && !is_separator(path_str[i + 2], path_env))
+				char next = path_str[i + 1];
+				switch
 				{
-					dots = 0;
+					case next == '.':
+						dots = 2;
+						is_last = i == path_len - 2;
+						if (!is_last && !is_separator(path_str[i + 2], path_env))
+						{
+							dots = 0;
+						}
+					case !is_separator(next, path_env):
+						dots = 0;
 				}
 			}
 			switch (dots)
@@ -251,7 +345,7 @@ fn String! normalize(String path_str, PathEnv path_env = DEFAULT_PATH_ENV)
 					continue;
 				case 2:
 					// This is an error: /a/../..
-					if (len == path_start && has_root) return PathResult.INVALID_PATH!;
+					if (len == path_start && has_root) return PathResult.INVALID_PATH?;

 					// If this .. at the start, or after ../? If so, we just copy ..
 					if (len == path_start ||
@@ -278,7 +372,7 @@ fn String! normalize(String path_str, PathEnv path_env = DEFAULT_PATH_ENV)
 					}
 					// Reading, we go from /../abc to /../abc
 					//                      ^            ^
- 					i += 2;
+					i += 2;
 					continue;
 				default:
 					break;
@@ -294,16 +388,16 @@ fn String! normalize(String path_str, PathEnv path_env = DEFAULT_PATH_ENV)
 	return path_str[:len];
 }

-fn ZString Path.as_zstr(Path path) => (ZString)path.path_string.ptr;
+fn ZString Path.as_zstr(self) => (ZString)self.path_string.ptr;

-fn String Path.root_directory(Path path)
+fn String Path.root_directory(self)
 {
-	String path_str = path.as_str();
+	String path_str = self.str_view();
 	usz len = path_str.len;
 	if (!len) return "";
-	if (path.env == PathEnv.WIN32)
+	if (self.env == PathEnv.WIN32)
 	{
-		usz root_len = volume_name_len(path_str, path.env)!!;
+		usz root_len = volume_name_len(path_str, self.env)!!;
 		if (root_len == len || !is_win32_separator(path_str[root_len])) return "";
 		return path_str[root_len..root_len];
 	}
@@ -318,24 +412,57 @@ fn String Path.root_directory(Path path)
 	return path_str;
 }

+def PathWalker = fn bool! (Path, bool is_dir, void*);

-fn String Path.as_str(Path path)
+/*
+ * Walk the path recursively. PathWalker is run on every file and
+ * directory found. Return true to abort the walk.
+ */
+fn bool! Path.walk(self, PathWalker w, void* data)
 {
-	return path.path_string;
+	const PATH_MAX = 512;
+	@stack_mem(PATH_MAX; Allocator* allocator)
+	{
+		Path abs = self.absolute(allocator)!;
+		PathList files = ls(abs, .allocator = allocator)!;
+		foreach (f : files)
+		{
+			if (f.str_view() == "." || f.str_view() == "..") continue;
+			f = abs.append(f.str_view(), allocator)!;
+			bool is_directory = is_dir(f);
+			if (w(f, is_directory, data)!) return true;
+			if (is_directory && f.walk(w, data)!) return true;
+		}
+	};
+	return false;
+}
+
+fn String Path.str_view(self) @inline
+{
+	return self.path_string;
 }


-fn bool Path.has_suffix(Path path, String str)
+fn bool Path.has_suffix(self, String str)
 {
-	return path.as_str().ends_with(str);
+	return self.str_view().ends_with(str);
+}
+
+fn void Path.free(self)
+{
+	free(self.path_string.ptr);
 }


-fn void Path.free(Path path)
+fn usz! Path.to_format(&self, Formatter* formatter) @dynamic
 {
-	free(path.path_string.ptr);
+	return formatter.print(self.str_view());
 }

+fn String Path.to_new_string(&self, Allocator* allocator = mem::heap()) @dynamic
+{
+	return self.str_view().copy(allocator);
+}

 const bool[256] RESERVED_PATH_CHAR_POSIX = {
 	[0] = true,
@@ -364,5 +491,4 @@ macro bool is_reserved_path_char(char c, PathEnv path_env = DEFAULT_PATH_ENV)
 	return path_env == PathEnv.WIN32
 		? RESERVED_PATH_CHAR_WIN32[c]
 		: RESERVED_PATH_CHAR_POSIX[c];
-}
-
+}
--- a/lib/std/io/stream.c3
+++ b/lib/std/io/stream.c3
@@ -0,0 +1,233 @@
+module std::io;
+
+interface InStream
+{
+	fn void! close() @optional;
+	fn usz! seek(isz offset, Seek seek) @optional;
+	fn usz len() @optional;
+	fn usz! available() @optional;
+	fn usz! read(char[] buffer);
+	fn char! read_byte();
+	fn usz! write_to(OutStream* out) @optional;
+	fn void! pushback_byte() @optional;
+}
+
+
+interface OutStream
+{
+	fn void! destroy() @optional;
+	fn void! close() @optional;
+	fn void! flush() @optional;
+	fn usz! write(char[] bytes);
+	fn void! write_byte(char c);
+	fn usz! read_to(InStream* in) @optional;
+}
+
+fn usz! available(InStream* s)
+{
+	if (&s.available) return s.available();
+	if (&s.seek)
+	{
+		usz curr = s.seek(0, Seek.CURSOR)!;
+		usz len = s.seek(0, Seek.END)!;
+		s.seek(curr, Seek.SET)!;
+		return len - curr;
+	}
+	return 0;
+}
+
+macro bool @is_instream(#expr)
+{
+	return $assignable(#expr, InStream*);
+}
+
+macro bool @is_outstream(#expr)
+{
+	return $assignable(#expr, OutStream*);
+}
+
+/**
+ * @param [&out] ref
+ * @require @is_instream(stream)
+ **/
+macro usz! read_any(stream, any* ref)
+{
+	return read_all(stream, ((char*)ref)[:ref.type.sizeof]);
+}
+
+/**
+ * @param [&in] ref "the object to write."
+ * @require @is_outstream(stream)
+ * @ensure return == ref.type.sizeof
+ */
+macro usz! write_any(stream, any* ref)
+{
+	return write_all(stream, ((char*)ref)[:ref.type.sizeof]);
+}
+
+/**
+ * @require @is_instream(stream)
+ */
+macro usz! read_all(stream, char[] buffer)
+{
+	if (buffer.len == 0) return 0;
+	usz n = stream.read(buffer)!;
+	if (n != buffer.len) return IoError.UNEXPECTED_EOF?;
+	return n;
+}
+
+/**
+ * @require @is_outstream(stream)
+ */
+macro usz! write_all(stream, char[] buffer)
+{
+	if (buffer.len == 0) return 0;
+	usz n = stream.write(buffer)!;
+	if (n != buffer.len) return IoError.INCOMPLETE_WRITE?;
+	return n;
+}
+
+macro usz! @read_using_read_byte(&s, char[] buffer)
+{
+	usz len = 0;
+	foreach (&cptr : buffer)
+	{
+		char! c = s.read_byte();
+		if (catch err = c)
+		{
+			case IoError.EOF: return len;
+			default: return err?;
+		}
+		*cptr = c;
+		len++;
+	}
+	return len;
+}
+
+macro void! @write_byte_using_write(&s, char c)
+{
+	char[1] buff = { c };
+	(*s).write(&buff)!;
+}
+
+
+macro char! @read_byte_using_read(&s)
+{
+	char[1] buffer;
+	usz read = (*s).read(&buffer)!;
+	if (read != 1) return IoError.EOF?;
+	return buffer[0];
+}
+
+def ReadByteFn = fn char!();
+
+
+macro usz! @write_using_write_byte(&s, char[] bytes)
+{
+	foreach (c : bytes) s.write_byte(self, c)!;
+	return bytes.len;
+}
+
+macro void! @pushback_using_seek(&s)
+{
+	s.seek(-1, CURSOR)!;
+}
+
+fn usz! copy_to(InStream* in, OutStream* dst, char[] buffer = {})
+{
+	if (buffer.len) return copy_through_buffer(in, dst, buffer);
+	if (&in.write_to) return in.write_to(dst);
+	if (&dst.read_to) return dst.read_to(in);
+	$switch (env::MEMORY_ENV)
+		$case NORMAL:
+			@pool()
+			{
+				return copy_through_buffer(in, dst, mem::temp_array(char, 4096));
+			};
+		$case SMALL:
+			@pool()
+			{
+				return copy_through_buffer(in, dst, mem::temp_array(char, 1024));
+			};
+		$case TINY:
+		$case NONE:
+			return copy_through_buffer(in, dst, &&(char[256]{}));
+	$endswitch
+}
+
+macro usz! copy_through_buffer(InStream *in, OutStream* dst, char[] buffer) @local
+{
+	usz total_copied;
+	while (true)
+	{
+		usz! len = in.read(buffer);
+		if (catch err = len)
+		{
+			case IoError.EOF: return total_copied;
+			default: return err?;
+		}
+		if (!len) return total_copied;
+		usz written = dst.write(buffer[:len])!;
+		total_copied += len;
+		if (written != len) return IoError.INCOMPLETE_WRITE?;
+	}
+}
+
+const char[*] MAX_VARS @private = { [2] = 3, [4] = 5, [8] = 10 };
+
+/**
+ * @require @is_instream(stream)
+ * @require @typekind(x_ptr) == POINTER && $typeof(x_ptr).inner.kindof.is_int()
+ **/
+macro usz! read_varint(stream, x_ptr)
+{
+	var $Type = $typefrom($typeof(x_ptr).inner);
+	const MAX = MAX_VARS[$Type.sizeof];
+	$Type x;
+	uint shift;
+	usz n;
+	for (usz i = 0; i < MAX; i++)
+	{
+		char! c = stream.read_byte();
+		if (catch err = c)
+		{
+			case IoError.EOF:
+				return IoError.UNEXPECTED_EOF?;
+			default:
+				return err?;
+		}
+		n++;
+		if (c & 0x80 == 0)
+		{
+			if (i + 1 == MAX && c > 1) break;
+			x |= c << shift;
+			$if $Type.kindof == SIGNED_INT:
+				x = x & 1 == 0 ? x >> 1 : ~(x >> 1);
+			$endif
+			*x_ptr = x;
+			return n;
+		}
+		x |= (c & 0x7F) << shift;
+		shift += 7;
+	}
+	return MathError.OVERFLOW?;
+}
+/**
+ * @require @is_outstream(stream)
+ * @require @typekind(x).is_int()
+ **/
+macro usz! write_varint(stream, x)
+{
+	var $Type = $typeof(x);
+	const MAX = MAX_VARS[$Type.sizeof];
+	char[MAX] buffer @noinit;
+	usz i;
+	while (x >= 0x80)
+	{
+		buffer[i] = (char)(x | 0x80);
+		x >>= 7;
+		i++;
+	}
+	buffer[i] = (char)x;
+	return write_all(stream, buffer[:i + 1]);
+}
--- a/lib/std/io/stream/buffer.c3
+++ b/lib/std/io/stream/buffer.c3
@@ -0,0 +1,133 @@
+module std::io;
+
+struct ReadBuffer (InStream)
+{
+	InStream* wrapped_stream;
+	char[] bytes;
+	usz read_idx;
+	usz write_idx;
+}
+
+/**
+ * Buffer reads from a stream.
+ * @param [inout] self
+ * @require bytes.len > 0
+ * @require self.bytes.len == 0 "Init may not run on already initialized data"
+ **/
+fn ReadBuffer* ReadBuffer.init(&self, InStream* wrapped_stream, char[] bytes)
+{
+	*self = { .wrapped_stream = wrapped_stream, .bytes = bytes };
+	return self;
+}
+fn String ReadBuffer.str_view(&self) @inline
+{
+	return (String)self.bytes[self.read_idx:self.write_idx - self.read_idx];
+}
+
+fn void! ReadBuffer.close(&self) @dynamic
+{
+	if (&self.wrapped_stream.close) self.wrapped_stream.close()!;
+}
+
+fn usz! ReadBuffer.read(&self, char[] bytes) @dynamic
+{
+	if (self.read_idx == self.write_idx)
+	{
+		if (self.read_idx == 0 && bytes.len >= self.bytes.len)
+		{
+			// Read directly into the input buffer.
+			return self.wrapped_stream.read(bytes)!;
+		}
+		self.refill()!;
+	}
+	usz n = min(self.write_idx - self.read_idx, bytes.len);
+	bytes[:n] = self.bytes[self.read_idx:n];
+	self.read_idx += n;
+	return n;
+}
+
+fn char! ReadBuffer.read_byte(&self) @dynamic
+{
+	if (self.read_idx == self.write_idx) self.refill()!;
+	if (self.read_idx == self.write_idx) return IoError.EOF?;
+	char c = self.bytes[self.read_idx];
+	self.read_idx++;
+	return c;
+}
+
+fn void! ReadBuffer.refill(&self) @local @inline
+{
+	self.read_idx = 0;
+	self.write_idx = self.wrapped_stream.read(self.bytes)!;
+}
+
+struct WriteBuffer (OutStream)
+{
+	OutStream* wrapped_stream;
+	char[] bytes;
+	usz index;
+}
+
+/**
+ * Buffer writes to a stream. Call `flush` when done writing to the buffer.
+ * @param [inout] self
+ * @require bytes.len > 0 "Non-empty buffer required"
+ * @require self.bytes.len == 0 "Init may not run on already initialized data"
+ **/
+fn WriteBuffer* WriteBuffer.init(&self, OutStream* wrapped_stream, char[] bytes)
+{
+	*self = { .wrapped_stream = wrapped_stream, .bytes = bytes };
+	return self;
+}
+
+fn String WriteBuffer.str_view(&self) @inline
+{
+	return (String)self.bytes[:self.index];
+}
+
+fn void! WriteBuffer.close(&self) @dynamic
+{
+	if (&self.wrapped_stream.close) return self.wrapped_stream.close();
+}
+
+fn void! WriteBuffer.flush(&self) @dynamic
+{
+	self.write_pending()!;
+	if (&self.wrapped_stream.flush) self.wrapped_stream.flush()!;
+}
+
+fn usz! WriteBuffer.write(&self, char[] bytes) @dynamic
+{
+	usz n = self.bytes.len - self.index;
+	if (bytes.len < n)
+	{
+		// Enough room in the buffer.
+		self.bytes[self.index:bytes.len] = bytes[..];
+		self.index += bytes.len;
+		return bytes.len;
+	}
+	self.write_pending()!;
+	if (bytes.len >= self.bytes.len)
+	{
+		// Write directly to the stream.
+		return self.wrapped_stream.write(bytes);
+	}
+	// Buffer the data.
+	self.bytes[:bytes.len] = bytes[..];
+	self.index = bytes.len;
+	return bytes.len;
+}
+
+fn void! WriteBuffer.write_byte(&self, char c) @dynamic
+{
+	usz n = self.bytes.len - self.index;
+	if (n == 0) self.write_pending()!;
+	self.bytes[0] = c;
+	self.index = 1;
+}
+
+fn void! WriteBuffer.write_pending(&self) @local
+{
+	self.index -= self.wrapped_stream.write(self.bytes[:self.index])!;
+	if (self.index != 0) return IoError.INCOMPLETE_WRITE?;
+}
--- a/lib/std/io/stream/bytebuffer.c3
+++ b/lib/std/io/stream/bytebuffer.c3
@@ -0,0 +1,148 @@
+module std::io;
+import std::math;
+
+struct ByteBuffer (InStream, OutStream)
+{
+	Allocator* allocator;
+	usz max_read;
+	char[] bytes;
+	usz read_idx;
+	usz write_idx;
+	bool has_last;
+}
+
+/**
+ * ByteBuffer provides a streamable read/write buffer.
+ * max_read defines how many bytes might be kept before its internal buffer is shrinked.
+ * @require self.bytes.len == 0 "Buffer already initialized."
+ **/
+fn ByteBuffer*! ByteBuffer.init_new(&self, usz max_read, usz initial_capacity = 16, Allocator* allocator = mem::heap())
+{
+	*self = { .allocator = allocator, .max_read = max_read };
+	initial_capacity = max(initial_capacity, 16);
+	self.grow(initial_capacity)!;
+	return self;
+}
+
+fn ByteBuffer*! ByteBuffer.init_temp(&self, usz max_read, usz initial_capacity = 16)
+{
+	return self.init_new(max_read, initial_capacity, mem::temp());
+}
+
+/**
+ * @require buf.len > 0
+ * @require self.bytes.len == 0 "Buffer already initialized."
+ **/
+fn ByteBuffer*! ByteBuffer.init_with_buffer(&self, char[] buf)
+{
+	*self = { .max_read = buf.len, .bytes = buf };
+	return self;
+}
+
+fn void ByteBuffer.free(&self)
+{
+	if (self.allocator) self.allocator.free(self.bytes);
+	*self = {};
+}
+
+fn usz! ByteBuffer.write(&self, char[] bytes) @dynamic
+{
+	usz cap = self.bytes.len - self.write_idx;
+	if (cap < bytes.len) self.grow(bytes.len)!;
+	self.bytes[self.write_idx:bytes.len] = bytes[..];
+	self.write_idx += bytes.len;
+	return bytes.len;
+}
+
+fn void! ByteBuffer.write_byte(&self, char c) @dynamic
+{
+	usz cap = self.bytes.len - self.write_idx;
+	if (cap == 0) self.grow(1)!;
+	self.bytes[self.write_idx] = c;
+	self.write_idx++;
+}
+
+fn usz! ByteBuffer.read(&self, char[] bytes) @dynamic
+{
+	usz readable = self.write_idx - self.read_idx;
+	if (readable == 0)
+	{
+		self.has_last = false;
+		return IoError.EOF?;
+	}
+	usz n = min(readable, bytes.len);
+	bytes[:n] = self.bytes[self.read_idx:n];
+	self.read_idx += n;
+	self.has_last = n > 0;
+	self.shrink();
+	return n;
+}
+
+fn char! ByteBuffer.read_byte(&self) @dynamic
+{
+	usz readable = self.write_idx - self.read_idx;
+	if (readable == 0)
+	{
+		self.has_last = false;
+		return IoError.EOF?;
+	}
+	char c = self.bytes[self.read_idx];
+	self.read_idx++;
+	self.has_last = true;
+	self.shrink();
+	return c;
+}
+
+/*
+ * Only the last byte of a successful read can be pushed back.
+ */
+fn void! ByteBuffer.pushback_byte(&self) @dynamic
+{
+	if (!self.has_last) return IoError.EOF?;
+	assert(self.read_idx > 0);
+	self.read_idx--;
+	self.has_last = false;
+}
+
+fn usz! ByteBuffer.seek(&self, isz offset, Seek seek) @dynamic
+{
+	switch (seek)
+	{
+		case SET:
+			if (offset < 0 || offset > self.write_idx) return IoError.INVALID_POSITION?;
+			self.read_idx = offset;
+			return offset;
+		case CURSOR:
+			if ((offset < 0 && self.read_idx < -offset) ||
+				(offset > 0 && self.read_idx + offset > self.write_idx)) return IoError.INVALID_POSITION?;
+			self.read_idx += offset;
+		case END:
+			if (offset < 0 || offset > self.write_idx) return IoError.INVALID_POSITION?;
+			self.read_idx = self.write_idx - offset;
+	}
+	return self.read_idx;
+}
+
+fn usz! ByteBuffer.available(&self) @inline @dynamic
+{
+	return self.write_idx - self.read_idx;
+}
+
+fn void! ByteBuffer.grow(&self, usz n)
+{
+	n = math::next_power_of_2(n);
+	char* p = self.allocator.realloc_aligned(self.bytes, n, .alignment = char.alignof)!;
+	self.bytes = p[:n];
+}
+
+macro ByteBuffer.shrink(&self)
+{
+	if (self.read_idx >= self.max_read)
+	{
+		// Drop the read data besides the last byte (for pushback_byte).
+		usz readable = self.write_idx - self.read_idx;
+		self.bytes[:1 + readable] = self.bytes[self.read_idx - 1:1 + readable];
+		self.write_idx = 1 + readable;
+		self.read_idx = 1;
+	}
+}
--- a/lib/std/io/stream/bytereader.c3
+++ b/lib/std/io/stream/bytereader.c3
@@ -1,80 +1,68 @@
 module std::io;
-import std::math;

-struct ByteReader
+struct ByteReader (InStream)
 {
 	char[] bytes;
 	usz index;
 }

-fn void ByteReader.init(ByteReader* reader, char[] bytes)
+fn usz ByteReader.len(&self) @dynamic
 {
-	*reader = { .bytes = bytes };
+	return self.bytes.len;
 }

-fn Stream ByteReader.as_stream(ByteReader* reader)
+fn ByteReader* ByteReader.init(&self, char[] bytes)
 {
-	return { .fns = &bytereader_interface, .data = reader };
+	*self = { .bytes = bytes };
+	return self;
 }

-fn usz! ByteReader.read(ByteReader* reader, char[] bytes)
+fn usz! ByteReader.read(&self, char[] bytes) @dynamic
 {
-	if (reader.index >= reader.bytes.len) return IoError.EOF!;
-	usz len = math::min(reader.bytes.len - reader.index, bytes.len);
+	if (self.index >= self.bytes.len) return IoError.EOF?;
+	usz len = min(self.bytes.len - self.index, bytes.len);
 	if (len == 0) return 0;
-	mem::copy(bytes.ptr, &reader.bytes[reader.index], len);
-	reader.index += len;
+	mem::copy(bytes.ptr, &self.bytes[self.index], len);
+	self.index += len;
 	return len;
 }

-fn char! ByteReader.read_byte(ByteReader* reader)
+fn char! ByteReader.read_byte(&self) @dynamic
 {
-	if (reader.index >= reader.bytes.len) return IoError.EOF!;
-	return reader.bytes[reader.index++];
+	if (self.index >= self.bytes.len) return IoError.EOF?;
+	return self.bytes[self.index++];
 }

-fn void! ByteReader.pushback_byte(ByteReader* reader)
+fn void! ByteReader.pushback_byte(&self) @dynamic
 {
-	if (!reader.index) return IoError.INVALID_PUSHBACK!;
-	reader.index--;
+	if (!self.index) return IoError.INVALID_PUSHBACK?;
+	self.index--;
 }

-fn usz! ByteReader.seek(ByteReader* reader, isz offset, Seek seek)
+fn usz! ByteReader.seek(&self, isz offset, Seek seek) @dynamic
 {
 	isz new_index;
 	switch (seek)
 	{
 		case SET: new_index = offset;
-		case CURSOR: new_index = reader.index + offset;
-		case END: new_index = reader.bytes.len + offset;
+		case CURSOR: new_index = self.index + offset;
+		case END: new_index = self.bytes.len + offset;
 	}
-	if (new_index < 0) return IoError.INVALID_POSITION!;
-	reader.index = new_index;
+	if (new_index < 0) return IoError.INVALID_POSITION?;
+	self.index = new_index;
 	return new_index;
 }

-fn usz! ByteReader.write_stream(ByteReader* reader, Stream* writer)
+fn usz! ByteReader.write_to(&self, OutStream* writer) @dynamic
 {
-	if (reader.index >= reader.bytes.len) return 0;
-	usz written = writer.write(reader.bytes[reader.index..])?;
-	reader.index += written;
-	assert(reader.index <= reader.bytes.len);
+	if (self.index >= self.bytes.len) return 0;
+	usz written = writer.write(self.bytes[self.index..])!;
+	self.index += written;
+	assert(self.index <= self.bytes.len);
 	return written;
 }

-fn usz ByteReader.available(ByteReader* reader)
+fn usz! ByteReader.available(&self) @inline @dynamic
 {
-	return math::max((isz)0, (isz)reader.bytes.len - reader.index);
-}
-
-StreamInterface bytereader_interface = {
-	.len_fn = fn (s) => ((ByteReader*)s.data).bytes.len,
-	.read_fn = fn (s, char[] bytes) => ((ByteReader*)s.data).read(bytes) @inline,
-	.read_byte_fn = fn (s) => ((ByteReader*)s.data).read_byte() @inline,
-	.pushback_byte_fn = fn (s) => ((ByteReader*)s.data).pushback_byte() @inline,
-	.seek_fn = fn (s, offset, seek) => ((ByteReader*)s.data).seek(offset, seek) @inline,
-	.write_stream_fn = fn (s, writer) => ((ByteReader*)s.data).write_stream(writer) @inline,
-	.available_fn = fn (s) => ((ByteReader*)s.data).available() @inline,
-};
-
-
+	return max(0, self.bytes.len - self.index);
+}
--- a/lib/std/io/stream/bytewriter.c3
+++ b/lib/std/io/stream/bytewriter.c3
@@ -1,6 +1,6 @@
 module std::io;

-struct ByteWriter
+struct ByteWriter (OutStream)
 {
 	char[] bytes;
 	usz index;
@@ -8,112 +8,105 @@ struct ByteWriter
 }

 /**
- * @param [&inout] writer
- * @param [&in] using
- * @require writer.bytes.len == 0 "Init may not run on on already initialized data"
- * @ensure using != null, index == 0
+ * @param [&inout] self
+ * @param [&inout] allocator
+ * @require self.bytes.len == 0 "Init may not run on on already initialized data"
+ * @ensure (bool)allocator, self.index == 0
 **/
-fn void ByteWriter.init(ByteWriter* writer, Allocator* using = mem::heap())
+fn ByteWriter* ByteWriter.init_new(&self, Allocator* allocator = mem::heap())
 {
-	*writer = { .bytes = {}, .allocator = using };
-}
-
-fn void ByteWriter.init_buffer(ByteWriter* writer, char[] data)
-{
-	*writer = { .bytes = data, .allocator = null };
+	*self = { .bytes = {}, .allocator = allocator };
+	return self;
 }

 /**
- * @param [&inout] writer
- * @require writer.bytes.len == 0 "Init may not run on on already initialized data"
+ * @param [&inout] self
+ * @require self.bytes.len == 0 "Init may not run on on already initialized data"
+ * @ensure self.index == 0
 **/
-fn void ByteWriter.tinit(ByteWriter* writer)
+fn ByteWriter* ByteWriter.init_temp(&self)
 {
-	*writer = { .bytes = {}, .allocator = mem::temp() };
+	return self.init_new(mem::temp());
 }

-fn Stream ByteWriter.as_stream(ByteWriter* writer)
+fn ByteWriter* ByteWriter.init_with_buffer(&self, char[] data)
 {
-	return { .fns = &bytewriter_interface, .data = writer };
+	*self = { .bytes = data, .allocator = null };
+	return self;
 }

-fn void ByteWriter.destroy(ByteWriter* writer)
+fn void! ByteWriter.destroy(&self) @dynamic
 {
-	if (!writer.allocator) return;
-	if (void* ptr = writer.bytes.ptr) free(ptr, .using = writer.allocator);
-	*writer = { };
+	if (!self.allocator) return;
+	if (void* ptr = self.bytes.ptr) self.allocator.free(ptr);
+	*self = { };
 }

-fn String ByteWriter.as_str(ByteWriter* writer)
+fn String ByteWriter.str_view(&self) @inline
 {
-	return (String)writer.bytes[:writer.index];
+	return (String)self.bytes[:self.index];
 }

-fn void! ByteWriter.ensure_capacity(ByteWriter* writer, usz len) @inline
+fn void! ByteWriter.ensure_capacity(&self, usz len) @inline
 {
-	if (writer.bytes.len > len) return;
-	if (!writer.allocator) return IoError.OUT_OF_SPACE!;
+	if (self.bytes.len > len) return;
+	if (!self.allocator) return IoError.OUT_OF_SPACE?;
 	if (len < 16) len = 16;
 	usz new_capacity = math::next_power_of_2(len);
-	char* new_ptr = realloc_checked(writer.bytes.ptr, new_capacity, .using = writer.allocator)?;
-	writer.bytes = new_ptr[:new_capacity];
+	char* new_ptr = self.allocator.realloc_checked(self.bytes.ptr, new_capacity)!;
+	self.bytes = new_ptr[:new_capacity];
 }

-fn usz! ByteWriter.write(ByteWriter* writer, char[] bytes)
+fn usz! ByteWriter.write(&self, char[] bytes) @dynamic
 {
-	writer.ensure_capacity(writer.index + bytes.len)?;
-	mem::copy(&writer.bytes[writer.index], bytes.ptr, bytes.len);
-	writer.index += bytes.len;
+	self.ensure_capacity(self.index + bytes.len)!;
+	mem::copy(&self.bytes[self.index], bytes.ptr, bytes.len);
+	self.index += bytes.len;
 	return bytes.len;
 }

-fn void! ByteWriter.write_byte(ByteWriter* writer, char c)
+fn void! ByteWriter.write_byte(&self, char c) @dynamic
 {
-	writer.ensure_capacity(writer.index + 1)?;
-	writer.bytes[writer.index++] = c;
+	self.ensure_capacity(self.index + 1)!;
+	self.bytes[self.index++] = c;
 }

 /**
- * @param [&inout] writer
- * @param [&inout] reader
+ * @param [&inout] self
+ * @param reader
 **/
-fn usz! ByteWriter.read_from(ByteWriter* writer, Stream* reader)
+fn usz! ByteWriter.read_from(&self, InStream* reader) @dynamic
 {
-	if (reader.supports_available())
+	usz start_index = self.index;
+	if (&reader.available)
 	{
-		usz total_read = 0;
-		while (usz available = reader.available()?)
+		while (usz available = reader.available()!)
 		{
-			writer.ensure_capacity(writer.index + available)?;
-			usz len = reader.read(writer.bytes[writer.index..])?;
-			total_read += len;
-			writer.index += len;
+			self.ensure_capacity(self.index + available)!;
+			usz read = reader.read(self.bytes[self.index..])!;
+			self.index += read;
 		}
-		return total_read;
+		return self.index - start_index;
+	}
+	if (self.bytes.len == 0)
+	{
+		self.ensure_capacity(16)!;
 	}
-	usz total_read = 0;
 	while (true)
 	{
 		// See how much we can read.
-		usz len_to_read = writer.bytes.len - writer.index;
+		usz len_to_read = self.bytes.len - self.index;
 		// Less than 16 bytes? Double the capacity
 		if (len_to_read < 16)
 		{
-			writer.ensure_capacity(writer.bytes.len * 2)?;
+			self.ensure_capacity(self.bytes.len * 2)!;
+			len_to_read = self.bytes.len - self.index;
 		}
 		// Read into the rest of the buffer
-		usz read = reader.read(writer.bytes[writer.index..])?;
-		writer.index += read;
+		usz read = reader.read(self.bytes[self.index..])!;
+		self.index += read;
 		// Ok, we reached the end.
-		if (read < len_to_read) return total_read;
+		if (read < len_to_read) return self.index - start_index;
 		// Otherwise go another round
 	}
 }
-
-StreamInterface bytewriter_interface = {
-	.destroy_fn = fn (s) => ((ByteWriter*)s.data).destroy(),
-	.len_fn = fn (s) => ((ByteWriter*)s.data).bytes.len,
-	.write_fn = fn (s, char[] bytes) => ((ByteWriter*)s.data).write(bytes),
-	.write_byte_fn = fn (s, char c) => ((ByteWriter*)s.data).write_byte(c),
-	.read_stream_fn = fn (s, reader) => ((ByteWriter*)s.data).read_from(reader),
-};
--- a/lib/std/io/stream/dstringwriter.c3
+++ b/lib/std/io/stream/dstringwriter.c3
@@ -1,14 +0,0 @@
-module std::io;
-
-fn Stream DString.as_stream(DString* dstring)
-{
-	return { .fns = &dstring_interface, .data = dstring };
-}
-
-StreamInterface dstring_interface = {
-	.destroy_fn = fn (s) => ((DString*)s.data).free(),
-	.len_fn = fn (s) => ((DString*)s.data).len(),
-	.write_fn = fn (s, char[] bytes) { ((DString*)s.data).append_chars((String)bytes); return bytes.len; },
-	.write_byte_fn = fn (s, char c) => ((DString*)s.data).append_char(c),
-	.read_stream_fn = fn (s, reader) => ((DString*)s.data).read_from_stream(reader),
-};
--- a/lib/std/io/stream/filestream.c3
+++ b/lib/std/io/stream/filestream.c3
@@ -1,18 +0,0 @@
-module std::io;
-
-fn Stream File.as_stream(File* file)
-{
-	return { .fns = &filestream_interface, .data = file };
-}
-
-StreamInterface filestream_interface = {
-	.close_fn = fn (s) => ((File*)s.data).close(),
-	.seek_fn = fn (s, offset, seek) => ((File*)s.data).seek(offset, seek) @inline,
-	.read_fn = fn (s, char[] bytes) => ((File*)s.data).read(bytes) @inline,
-	.write_fn = fn (s, char[] bytes) => ((File*)s.data).write(bytes) @inline,
-	.write_byte_fn = fn (s, char c) => ((File*)s.data).putc(c) @inline,
-	.read_byte_fn = fn (s) => ((File*)s.data).getc() @inline,
-	.flush_fn = fn (s) => ((File*)s.data).flush() @inline,
-};
-
-
--- a/lib/std/io/stream/limitreader.c3
+++ b/lib/std/io/stream/limitreader.c3
@@ -0,0 +1,44 @@
+module std::io;
+
+struct LimitReader (InStream)
+{
+	InStream* wrapped_stream;
+	usz limit;
+}
+
+/**
+ * @param [&inout] wrapped_stream "The stream to read from"
+ * @param limit "The max limit to read"
+ **/
+fn LimitReader* LimitReader.init(&self, InStream* wrapped_stream, usz limit)
+{
+	*self = { .wrapped_stream = wrapped_stream, .limit = limit };
+	return self;
+}
+
+fn void! LimitReader.close(&self) @dynamic
+{
+	if (&self.wrapped_stream.close) return self.wrapped_stream.close();
+}
+
+
+fn usz! LimitReader.read(&self, char[] bytes) @dynamic
+{
+	if (self.limit == 0) return IoError.EOF?;
+	usz m = min(bytes.len, self.limit);
+	usz n = self.wrapped_stream.read(bytes[:m])!;
+	self.limit -= n;
+	return n;
+}
+
+fn char! LimitReader.read_byte(&self) @dynamic
+{
+	if (self.limit == 0) return IoError.EOF?;
+	defer try self.limit--;
+	return self.wrapped_stream.read_byte();
+}
+
+fn usz! LimitReader.available(&self) @inline @dynamic
+{
+	return self.limit;
+}
--- a/lib/std/io/stream/scanner.c3
+++ b/lib/std/io/stream/scanner.c3
@@ -0,0 +1,124 @@
+module std::io;
+
+struct Scanner (InStream)
+{
+	InStream* wrapped_stream;
+	char[] buf;
+	usz pattern_idx;
+	usz read_idx;
+}
+
+/**
+ * Scanner provides a way to read delimited data (with newlines as the default).
+ * The supplied buffer must be at least as large as the expected data length
+ * including its pattern.
+ *
+ * @param [&in] stream "The stream to read data from."
+ * @require buffer.len > 0 "Non-empty buffer required."
+ **/
+fn void Scanner.init(&self, InStream* stream, char[] buffer)
+{
+	*self = { .wrapped_stream = stream, .buf = buffer };
+}
+
+
+/**
+ * Return and clear any remaining unscanned data.
+ **/
+fn char[] Scanner.flush(&self) @dynamic
+{
+	assert(self.read_idx >= self.pattern_idx);
+	usz n = self.read_idx - self.pattern_idx;
+	char[] buf = self.buf[self.pattern_idx:n];
+	self.pattern_idx = 0;
+	self.read_idx = 0;
+	return buf;
+}
+
+fn void! Scanner.close(&self) @dynamic
+{
+	if (&self.wrapped_stream.close) return self.wrapped_stream.close();
+}
+
+/**
+ * Scan the stream for the next split character and return data up to the match.
+ * @require pattern.len > 0 "Non-empty pattern required."
+ * @require self.buf.len > pattern.len "Pattern too large."
+ **/
+fn char[]! Scanner.scan(&self, String pattern = "\n")
+{
+	if (self.read_idx == 0)
+	{
+		// First read.
+		self.read_idx = self.refill(self.buf)!;
+		self.pattern_idx = 0;
+	}
+	assert(self.read_idx >= self.pattern_idx);
+	usz n = self.read_idx - self.pattern_idx;
+	char[] buf = self.buf[self.pattern_idx:n];
+	if (try i = self.find(buf, pattern))
+	{
+		self.pattern_idx += i + pattern.len;
+		return buf[:i];
+	}
+	if (self.pattern_idx == 0 || self.read_idx < self.buf.len)
+	{
+		// Split pattern not found with maximized search, abort.
+		// Split pattern not found and already read as much as possible.
+		return SearchResult.MISSING?;
+	}
+	// Split pattern not found: maximize the search and try one more time.
+	self.buf[:n] = buf[..];
+	self.pattern_idx = 0;
+
+	buf = self.buf[n..];
+	usz p = self.refill(buf)!;
+	self.read_idx = n + p;
+
+	buf = buf[:p];
+	usz i = self.find(buf, pattern)!;
+	self.pattern_idx = n + i + pattern.len;
+
+	return self.buf[:n + i];
+}
+
+macro usz! Scanner.find(&self, buf, pattern) @private
+{
+	return ((String)buf).index_of(pattern);
+}
+
+macro usz! Scanner.refill(&self, buf) @private
+{
+	usz! n = self.wrapped_stream.read(buf);
+	if (catch err = n)
+	{
+		case IoError.EOF:
+			return SearchResult.MISSING?;
+		default:
+			return err?;
+	}
+	return n;
+}
+
+fn usz! Scanner.read(&self, char[] bytes) @dynamic
+{
+	usz n;
+	if (self.pattern_idx < self.read_idx)
+	{
+		n = min(bytes.len, self.read_idx - self.pattern_idx);
+		bytes[:n] = self.buf[self.pattern_idx:n];
+		self.pattern_idx += n;
+		bytes = bytes[n..];
+	}
+	n += self.wrapped_stream.read(bytes)!;
+	return n;
+}
+
+fn char! Scanner.read_byte(&self) @dynamic
+{
+	if (self.pattern_idx < self.read_idx)
+	{
+		return self.buf[self.pattern_idx++];
+	}
+	return self.wrapped_stream.read_byte();
+}
--- a/lib/std/libc/libc.c3
+++ b/lib/std/libc/libc.c3
@@ -11,14 +11,14 @@ const int RAND_MAX = 0x7fffffff;

 struct DivResult
 {
-    int quot;
-    int rem;
+	CInt quot;
+	CInt rem;
 }

 struct LongDivResult
 {
-    long quot;
-    long rem;
+	CLong quot;
+	CLong rem;
 }

 fn Errno errno()
@@ -31,73 +31,200 @@ fn void errno_set(Errno e)
 	os::errno_set((int)e);
 }

-typedef TerminateFunction = fn void();
-typedef CompareFunction = fn int(void*, void*);
-typedef JmpBuf = uptr[$$JMP_BUF_SIZE];
+distinct Errno = inline CInt;
+def TerminateFunction = fn void();
+def CompareFunction = fn int(void*, void*);
+def JmpBuf = uptr[$$JMP_BUF_SIZE];
+def Fd = CInt;
+def Fpos_t = long; // TODO make sure fpos is correct on all targets.
+def SignalFunction = fn void(CInt);

-$if (env::COMPILER_LIBC_AVAILABLE)
+const CInt SIGHUP = 1;
+const CInt SIGINT = 2;
+const CInt SIGQUIT = 3;
+const CInt SIGILL = 4;
+const CInt SIGTRAP = 5;
+const CInt SIGABTR = 6;
+const CInt SIGBUS = BSD_FLAVOR_SIG ? 10 : 7; // Or Mips
+const CInt SIGFPE = 8;
+const CInt SIGKILL = 9;
+const CInt SIGSEGV = 11;
+const CInt SIGSYS = BSD_FLAVOR_SIG ? 12 : 31;
+const CInt SIGPIPE = 13;
+const CInt SIGALRM = 14;
+const CInt SIGTERM = 15;
+const CInt SIGURG = BSD_FLAVOR_SIG ? 16 : 23;
+const CInt SIGSTOP = BSD_FLAVOR_SIG ? 17 : 19;
+const CInt SIGTSTP = BSD_FLAVOR_SIG ? 18 : 20;
+const CInt SIGCONT = BSD_FLAVOR_SIG ? 19 : 18;
+const CInt SIGCHLD = BSD_FLAVOR_SIG ? 20 : 17;

+const bool BSD_FLAVOR_SIG @local = env::OPENBSD || env::DARWIN || env::FREEBSD || env::NETBSD;
+
+def Time_t = $typefrom(env::WIN32 ? long.typeid : CLong.typeid);
+def Off_t = $typefrom(env::WIN32 ? int.typeid : usz.typeid);
+
+struct Timespec
+{
+	Time_t tv_sec;
+	CLong tv_nsec;
+}
+
+module libc @if(env::LIBC);
+
+extern fn void abort();
+extern fn CInt abs(CInt n);
+extern fn ZString asctime(Tm* timeptr);
+extern fn ZString asctime_r(Tm* timeptr, char* buf);
+extern fn CInt atexit(TerminateFunction func);
 extern fn double atof(char* str);
 extern fn int atoi(char* str);
 extern fn CLongLong atoll(char* str);
-extern fn double strtod(char* str, char** endptr);
-extern fn CLong strtol(char* str, char** endptr, int base);
-extern fn CULong stroul(char* str, char** endptr, int base);
-extern fn void abort();
-extern fn void atexit(TerminateFunction f);
-extern fn void exit(int status);
-extern fn ZString getenv(ZString name);
-extern fn int setenv(ZString name, ZString value, int overwrite);
-extern fn int unsetenv(ZString name);
-extern fn int system(char* str);
 extern fn void bsearch(void* key, void *base, usz items, usz size, CompareFunction compare);
-extern fn void qsort(void* base, usz items, usz size, CompareFunction compare);
-extern fn DivResult div(int numer, int denom);
-extern fn long labs(long x);
-extern fn LongDivResult ldiv(long number, long denom);
-extern fn int rand();
-extern fn void srand(uint seed);
-
+extern fn void* calloc(usz count, usz size);
+extern fn void clearerr(CFile stream);
+extern fn Clock_t clock();
+extern fn CInt close(CInt fd) @if(!env::WIN32);
+extern fn double difftime(Time_t time1, Time_t time2) @if(!env::WIN32);
+extern fn DivResult div(CInt numer, CInt denom);
+extern fn void exit(CInt status);
+extern fn CInt fclose(CFile stream);
+extern fn CFile fdopen(CInt fd, ZString mode) @if(!env::WIN32);
+extern fn CInt feof(CFile stream);
+extern fn CInt ferror(CFile stream);
+extern fn CInt fflush(CFile stream);
+extern fn CInt fgetc(CFile stream);
+extern fn ZString fgets(char* string, CInt n, CFile stream);
+extern fn CInt fgetpos(CFile stream, Fpos_t* pos);
+extern fn Fd fileno(CFile stream) @if(!env::WIN32);
+extern fn CFile fopen(ZString filename, ZString mode);
+extern fn CInt fprintf(CFile stream, ZString format, ...);
+extern fn CInt fputc(CInt c, CFile stream);
+extern fn CInt fputs(ZString string, CFile stream);
+extern fn usz fread(void* ptr, usz size, usz nmemb, CFile stream);
+extern fn void* free(void*);
+extern fn CFile freopen(ZString filename, ZString mode, CFile stream);
+extern fn CInt fscanf(CFile stream, ZString format, ...);
+extern fn CInt fseek(CFile stream, SeekIndex offset, CInt whence) @if(!env::WIN32);
+extern fn CInt fsetpos(CFile stream, Fpos_t* pos);
+extern fn SeekIndex ftell(CFile stream) @if(!env::WIN32);
+extern fn usz fwrite(void* ptr, usz size, usz nmemb, CFile stream);
+extern fn CInt getc(CFile stream);
+extern fn CInt getchar();
+extern fn ZString getenv(ZString name);
+extern fn ZString gets(char* buffer);
+extern fn Tm* gmtime(Time_t* timer);
+extern fn Tm* gmtime_r(Time_t *timer, Tm* buf) @if(!env::WIN32);
+extern fn CLong labs(CLong x);
+extern fn LongDivResult ldiv(CLong number, CLong denom);
+extern fn Tm* localtime(Time_t* timer);
+extern fn Tm* localtime_r(Time_t* timer, Tm* result) @if(!env::WIN32);
 extern fn void longjmp(JmpBuf* buffer, CInt value);
-$if (env::OS_TYPE == OsType.WIN32)
-// TODO win32 aarch64
-extern fn CInt _setjmp(void* frameptr, JmpBuf* buffer);
-macro CInt setjmp(JmpBuf* buffer) => _setjmp($$frameaddress(), buffer);
-$else
-extern fn CInt setjmp(JmpBuf* buffer);
-$endif
-// MB functions omitted
-
-// string
-extern fn void* memchr(void* str, int c, usz n);
-extern fn int memcmp(void* str1, void* str2, usz n);
+extern fn void* malloc(usz size);
+extern fn void* memchr(void* str, CInt c, usz n);
+extern fn CInt memcmp(void* buf1, void* buf2, usz count);
 extern fn void* memcpy(void* dest, void* src, usz n);
 extern fn void* memmove(void* dest, void* src, usz n);
 extern fn void* memset(void* dest, CInt value, usz n);
-extern fn char* strcat(char* dest, char* src);
-extern fn char* strncat(char* dest, char* src, usz n);
-extern fn char* strchr(char* str, int c);
-extern fn int strcmp(char* str1, char* str2);
-extern fn int strncmp(char* str1, char* str2, usz n);
-extern fn int strcoll(char* str1, char* str2);
-extern fn char* strcpy(char* dst, char* src);
-extern fn char* strncpy(char* dst, char* src, usz n);
-extern fn usz strcspn(char* str1, char* str2);
-extern fn char* strerror(int errn);
-extern fn usz strlen(char* str);
-extern fn char* strpbrk(char* str1, char* str2);
-extern fn usz strspn(char* str1, char* str2);
-extern fn char* strstr(char* haystack, char* needle);
-extern fn char* strtok(char* str, char* delim);
-extern fn usz strxfrm(char* dest, char* src, usz n);
-
-// malloc
-extern fn void* malloc(usz size);
-extern fn void* calloc(usz count, usz size);
-extern fn void* free(void*);
+extern fn Time_t* mktime(Tm* time) @if(!env::WIN32);
+extern fn void perror(ZString string);
+extern fn CInt printf(ZString format, ...);
+extern fn CInt putc(CInt c, CFile stream);
+extern fn CInt putchar(CInt c);
+extern fn CInt puts(ZString str);
+extern fn void qsort(void* base, usz items, usz size, CompareFunction compare);
+extern fn CInt raise(CInt signal);
+extern fn CInt rand();
+extern fn isz read(Fd fd, void* buf, usz nbyte) @if(!env::WIN32);
 extern fn void* realloc(void* ptr, usz size);
+extern fn CInt remove(ZString filename);
+extern fn CInt rename(ZString old_name, ZString new_name);
+extern fn void rewind(CFile stream);
+extern fn CInt scanf(ZString format, ...);
+extern fn void setbuf(CFile stream, char* buffer);
+extern fn int setenv(ZString name, ZString value, CInt overwrite);
+extern fn CInt setjmp(JmpBuf* buffer) @if(!env::WIN32);
+extern fn void setvbuf(CFile stream, char* buf, CInt type, usz size);
+extern fn SignalFunction signal(CInt sig, SignalFunction function);
+extern fn CInt snprintf(char* buffer, usz size, ZString format, ...);
+extern fn CInt sprintf(char* buffer, ZString format, ...);
+extern fn void srand(uint seed);
+extern fn CInt sscanf(char* buffer, ZString format, ...);
+extern fn ZString strcat(ZString dest, ZString src);
+extern fn char* strchr(char* str, CInt c);
+extern fn CInt strcmp(ZString str1, ZString str2);
+extern fn CInt strcoll(ZString str1, ZString str2);
+extern fn usz strcspn(ZString str1, ZString str2);
+extern fn ZString strcpy(ZString dst, ZString src);
+extern fn ZString strerror(CInt errn);
+extern fn usz strftime(char* dest, usz maxsize, ZString format, Tm* timeptr);
+extern fn usz strlen(ZString str);
+extern fn ZString strncat(char* dest, char* src, usz n);
+extern fn CInt strncmp(char* str1, char* str2, usz n);
+extern fn char* strncpy(char* dst, char* src, usz n);
+extern fn CULong stroul(char* str, char** endptr, int base);
+extern fn char* strpbrk(ZString str1, ZString str2);
+extern fn usz strspn(ZString str1, ZString str2);
+extern fn ZString strptime(char* buf, ZString format, Tm* tm);
+extern fn char* strrchr(ZString str, CInt c);
+extern fn char* strstr(ZString haystack, ZString needle);
+extern fn double strtod(char* str, char** endptr);
+extern fn float strtof(char* str, char** endptr);
+extern fn ZString strtok(ZString str, ZString delim);
+extern fn CLong strtol(char* str, char** endptr, CInt base);
+extern fn CULong strtul(char* str, char** endptr, CInt base);
+extern fn usz strxfrm(char* dest, ZString src, usz n);
+extern fn CInt system(ZString str);
+extern fn Time_t timegm(Tm *timeptr) @if(!env::WIN32);
+extern fn ZString tmpnam(ZString str);
+extern fn CInt ungetc(CInt c, CFile stream);
+extern fn CInt unsetenv(ZString name);
+extern fn isz write(Fd fd, void* buffer, usz count) @if(!env::WIN32);

-$else
+extern fn CFile fmemopen(void* ptr, usz size, ZString mode);
+extern fn isz getline(char** linep, usz* linecapp, CFile stream);
+extern fn int timespec_get(TimeSpec* ts, int base);
+extern fn int nanosleep(TimeSpec* req, TimeSpec* remaining);
+extern fn ZString ctime(Time_t *timer);
+extern fn Time_t time(Time_t *timer);
+
+const CInt STDIN_FD = 0;
+const CInt STDOUT_FD = 1;
+const CInt STDERR_FD = 2;
+
+module libc @if(env::LINUX);
+extern CFile __stdin @extern("stdin");
+extern CFile __stdout @extern("stdout");
+extern CFile __stderr @extern("stderr");
+extern fn usz malloc_usable_size(void* ptr);
+macro usz malloc_size(void* ptr) => malloc_usable_size(ptr);
+extern fn void* aligned_alloc(usz align, usz size);
+macro CFile stdin() => __stdin;
+macro CFile stdout() => __stdout;
+macro CFile stderr() => __stderr;
+
+module libc @if(env::DARWIN);
+extern CFile __stdinp;
+extern CFile __stdoutp;
+extern CFile __stderrp;
+extern fn usz malloc_size(void* ptr);
+extern fn void* aligned_alloc(usz align, usz size);
+macro CFile stdin() => __stdinp;
+macro CFile stdout() => __stdoutp;
+macro CFile stderr() => __stderrp;
+
+module libc @if(env::WIN32);
+macro usz malloc_size(void* ptr) => _msize(ptr);
+macro CFile stdin() => __acrt_iob_func(STDIN_FD);
+macro CFile stdout() => __acrt_iob_func(STDOUT_FD);
+macro CFile stderr() => __acrt_iob_func(STDERR_FD);
+
+module libc @if(env::LIBC && !env::WIN32 && !env::LINUX && !env::DARWIN);
+macro CFile stdin() { return (CFile*)(uptr)STDIN_FD; }
+macro CFile stdout() { return (CFile*)(uptr)STDOUT_FD; }
+macro CFile stderr() { return (CFile*)(uptr)STDERR_FD; }
+
+module libc @if(!env::LIBC);

 fn void longjmp(JmpBuf* buffer, CInt value) @weak @extern("longjmp") @nostrip
 {
@@ -144,110 +271,6 @@ fn void* memset(void* dest, CInt value, usz n) @weak @extern("memset") @nostrip
 	return dest;
 }

-$endif
-
-// stdio
-
-typedef Fpos = long;
-typedef CFile = void*;
-
-$switch
-$case env::COMPILER_LIBC_AVAILABLE && env::OS_TYPE == OsType.LINUX:
-    extern CFile __stdin @extern("stdin");
-    extern CFile __stdout @extern("stdout");
-    extern CFile __stderr @extern("stderr");
-    extern fn usz malloc_usable_size(void* ptr);
-    macro usz malloc_size(void* ptr) { return malloc_usable_size(ptr); }
-	extern fn void* aligned_alloc(usz align, usz size);
-    macro CFile stdin() { return __stdin; }
-    macro CFile stdout() { return __stdout; }
-    macro CFile stderr() { return __stderr; }
-$case env::COMPILER_LIBC_AVAILABLE && env::OS_TYPE == OsType.MACOSX:
-    extern CFile __stdinp;
-    extern CFile __stdoutp;
-    extern CFile __stderrp;
-    extern fn usz malloc_size(void* ptr);
-    extern fn void* aligned_alloc(usz align, usz size);
-	macro CFile stdin() { return __stdinp; }
-    macro CFile stdout() { return __stdoutp; }
-    macro CFile stderr() { return __stderrp; }
-$case env::COMPILER_LIBC_AVAILABLE && env::OS_TYPE == OsType.WIN32:
-    extern fn CFile __acrt_iob_func(CInt c);
-    extern fn usz _msize(void* ptr);
-    macro usz malloc_size(void* ptr) { return _msize(ptr); }
-    macro CFile stdin() { return __acrt_iob_func(0); }
-    macro CFile stdout() { return __acrt_iob_func(1); }
-    macro CFile stderr() { return __acrt_iob_func(2); }
-$default:
-    macro CFile stdin() { return (CFile*)(uptr)0; }
-    macro CFile stdout() { return (CFile*)(uptr)1; }
-    macro CFile stderr() { return (CFile*)(uptr)2; }
-$endswitch
-
-const HAS_MALLOC_SIZE =
-	env::OS_TYPE == OsType.LINUX
-	|| env::OS_TYPE == OsType.WIN32
-	|| env::OS_TYPE == OsType.MACOSX;
-
-// The following needs to be set per arch+os
-// For now I have simply pulled the defaults from MacOS
-const int SEEK_SET = 0;
-const int SEEK_CUR = 1;
-const int SEEK_END = 2;
-const int _IOFBF = 0; // Fully buffered
-const int _IOLBF = 1; // Line buffered
-const int _IONBF = 2; // Unbuffered
-const int BUFSIZ = 1024;
-const int EOF = -1;
-const int FOPEN_MAX = 20;
-const int FILENAME_MAX = 1024;
-
-typedef Errno = distinct CInt;
-typedef SeekIndex = CLong;
-
-$if (env::COMPILER_LIBC_AVAILABLE)
-
-extern fn int fclose(CFile stream);
-extern fn void clearerr(CFile stream);
-extern fn int feof(CFile stream);
-extern fn int ferror(CFile stream);
-extern fn int fflush(CFile stream);
-extern fn int fgetpos(CFile stream, Fpos* pos);
-extern fn CFile fopen(ZString filename, ZString mode);
-extern fn usz fread(void* ptr, usz size, usz nmemb, CFile stream);
-extern fn CFile freopen(ZString filename, ZString mode, CFile stream);
-extern fn CFile fmemopen(void* ptr, usz size, ZString mode);
-extern fn int fseek(CFile stream, SeekIndex offset, int whence);
-extern fn int fsetpos(CFile stream, Fpos* pos);
-extern fn SeekIndex ftell(CFile stream);
-extern fn usz fwrite(void* ptr, usz size, usz nmemb, CFile stream);
-extern fn int remove(char* filename);
-extern fn int rename(char* old_name, char* new_name);
-extern fn void rewind(CFile stream);
-extern fn void setbuf(CFile stream, char* buffer);
-extern fn void setvbuf(CFile stream, char* buffer, int mode, usz size);
-extern fn CFile tmpnam(char* str);
-extern fn int fprintf(CFile stream, char* format, ...);
-extern fn int printf(char* format, ...);
-extern fn int sprintf(char* str, char* format, ...);
-extern fn int snprintf(char* str, usz size, char* format, ...);
-extern fn int fscanf(CFile stream, char* format, ...);
-extern fn int scanf(char* format, ...);
-extern fn int sscanf(char* str, char* format, ...);
-extern fn int fgetc(CFile stream);
-extern fn char* fgets(char* str, int n, CFile stream);
-extern fn int fputc(int c, CFile stream);
-extern fn int getc(CFile stream);
-extern fn int getchar();
-extern fn int putc(int c, CFile stream);
-extern fn int putchar(int c);
-extern fn int puts(char* str);
-extern fn int ungetc(int c, CFile stream);
-extern fn void perror(char* str);
-extern fn isz getline(char** linep, usz* linecapp, CFile stream);
-
-$else
-
 fn int fseek(CFile stream, SeekIndex offset, int whence) @weak @extern("fseek") @nostrip
 {
 	unreachable("'fseek' not available.");
@@ -315,150 +338,240 @@ fn int puts(ZString str) @weak @extern("puts") @nostrip
 	unreachable("'puts' not available.");
 }

-$endif
+module libc;
+
+// stdio
+
+def CFile = void*;
+
+
+const HAS_MALLOC_SIZE = env::LINUX || env::WIN32 || env::DARWIN;
+
+// The following needs to be set per arch+os
+// For now I have simply pulled the defaults from MacOS
+const int SEEK_SET = 0;
+const int SEEK_CUR = 1;
+const int SEEK_END = 2;
+const int _IOFBF = 0; // Fully buffered
+const int _IOLBF = 1; // Line buffered
+const int _IONBF = 2; // Unbuffered
+const int BUFSIZ = 1024;
+const int EOF = -1;
+const int FOPEN_MAX = 20;
+const int FILENAME_MAX = 1024;
+
+const S_IFMT   = 0o170000; // type of file mask
+const S_IFIFO  = 0o010000; // named pipe (fifo)
+const S_IFCHR  = 0o020000; // character special
+const S_IFDIR  = 0o040000; // directory
+const S_IFBLK  = 0o060000; // block special
+const S_IFREG  = 0o100000; // regular
+const S_IFLNK  = 0o120000; // symbolic link
+const S_IFSOCK = 0o140000; // socket
+const S_ISUID  = 0o004000; // Set user id on execution
+const S_ISGID  = 0o002000; // Set group id on execution
+const S_ISVTX  = 0o001000; // Save swapped text even after use
+const S_IRUSR  = 0o000400; // Read permission, owner
+const S_IWUSR  = 0o000200; // Write permission, owner
+const S_IXUSR  = 0o000100; // Execute/search permission, owner
+
+def SeekIndex = CLong;
+
 // vsprintf vprintf not supported

 // time.h

-typedef TimeOffset = CLong;
-
 struct Tm
 {
-	int	tm_sec;		/* seconds after the minute [0-60] */
-	int	tm_min;		/* minutes after the hour [0-59] */
-	int	tm_hour;	/* hours since midnight [0-23] */
-	int	tm_mday;	/* day of the month [1-31] */
-	int	tm_mon;		/* months since January [0-11] */
-	int	tm_year;	/* years since 1900 */
-	int	tm_wday;	/* days since Sunday [0-6] */
-	int	tm_yday;	/* days since January 1 [0-365] */
-	int	tm_isdst;	/* Daylight Savings Time flag */
-	TimeOffset tm_gmtoff;	/* offset from UTC in seconds */
-    char *tm_zone;	/* timezone abbreviation */
+	CInt	tm_sec;		// seconds after the minute [0-60]
+	CInt	tm_min;		// minutes after the hour [0-59]
+	CInt	tm_hour;	// hours since midnight [0-23]
+	CInt	tm_mday;	// day of the month [1-31]
+	CInt	tm_mon;		// months since January [0-11]
+	CInt	tm_year;	// years since 1900
+	CInt	tm_wday;	// days since Sunday [0-6]
+	CInt	tm_yday;	// days since January 1 [0-365]
+	CInt	tm_isdst;	// Daylight Savings Time flag
+	TimeOffset tm_gmtoff @if(!env::WIN32);	/* offset from UTC in seconds */
+	char *tm_zone @if(!env::WIN32);	/* timezone abbreviation */
+	CInt tm_nsec @if(env::WASI);
 }

 struct TimeSpec
 {
-	Time s;
-	ulong ns;
+	Time_t s;
+	ulong ns @if(env::WIN32);
+	CLong ns @if(!env::WIN32);
 }

+
+def Clock_t = int @if(env::WIN32);
+def Clock_t = CULong @if(!env::WIN32);
+
+def TimeOffset = int @if(env::WASI) ;
+def TimeOffset = CLong @if(!env::WASI) ;
+
 const int TIME_UTC = 1;


-extern fn int timespec_get(TimeSpec* ts, int base);
-extern fn int nanosleep(TimeSpec* req, TimeSpec* remaining);
-
 // Likely wrong, must be per platform.
 const CLOCKS_PER_SEC = 1000000;

-// Time also needs to be per platform
-typedef Time = long;
-typedef Clock = ulong;
-
-extern fn ZString asctime(Tm *timeptr);
-extern fn Clock clock();
-extern fn ZString ctime(Time *timer);
-extern fn double difftime(Time time1, Time time2);
-extern fn Tm* gmtime(Time *timer);
-extern fn Tm* localtime(Time *timer);
-extern fn Time mktime(Tm *timeptr);
-extern fn usz strftime(char* str, usz maxsize, char* format, Tm *timeptr);
-extern fn Time time(Time *timer);
-
-// signal
-typedef SignalFunction = fn void(int);
-extern fn SignalFunction signal(int sig, SignalFunction function);
-// Incomplete
-
-
 module libc::errno;

-const Errno OK = 0;
-const Errno EPERM = 1;      // Operation not permitted
-const Errno ENOENT = 2;     // No such file or directory
-const Errno ESRCH = 3;      // No such process
-const Errno EINTR = 4;      // Interrupted system call
-const Errno EIO = 5;        // I/O error
-const Errno ENXIO = 6;      // No such device or address
-const Errno E2BIG = 7;      // Argument list too long
-const Errno ENOEXEC = 8;    // Exec format error
-const Errno EBADF = 9;      // Bad file number
-const Errno ECHILD = 10;    // No child processes
+const Errno OK                       = 0;
+const Errno EPERM                    = 1; // Operation not permitted
+const Errno ENOENT                   = 2; // No such file or directory
+const Errno ESRCH                    = 3; // No such process
+const Errno EINTR                    = 4; // Interrupted system call
+const Errno EIO                      = 5; // I/O error
+const Errno ENXIO                    = 6; // No such device or address
+const Errno E2BIG                    = 7; // Argument list too long
+const Errno ENOEXEC                  = 8; // Exec format error
+const Errno EBADF                    = 9; // Bad file number
+const Errno ECHILD                   = 10; // No child processes

-$if (env::OS_TYPE == MACOSX)
-const Errno EAGAIN = 35;    // Try again Macos
-$else
-const Errno EAGAIN = 11;    // Try again
-$endif

-const Errno ENOMEM = 12;    // Out of memory
-const Errno EACCES = 13;    // Permission denied
-const Errno EFAULT = 14;    // Bad address
-const Errno ENOTBLK = 15;   // Block device required, not on Win32
-const Errno EBUSY = 16;     // Device or resource busy
-const Errno EEXIST = 17;    // File exists
-const Errno EXDEV = 18;     // Cross-device link
-const Errno ENODEV = 19;    // No such device
-const Errno ENOTDIR = 20;   // Not a directory
-const Errno EISDIR = 21;    // Is a directory
-const Errno EINVAL = 22;    // Invalid argument
-const Errno ENFILE = 23;    // File table overflow
-const Errno EMFILE = 24;    // Too many open files
-const Errno ENOTTY = 25;    // Not a typewriter
-const Errno ETXTBSY = 26;   // Text file busy, not on Win32
-const Errno EFBIG = 27;     // File too large
-const Errno ENOSPC = 28;    // No space left on device
-const Errno ESPIPE = 29;    // Illegal seek
-const Errno EROFS = 30;     // Read-only file system
-const Errno EMLINK = 31;    // Too many links
-const Errno EPIPE = 32;     // Broken pipe
-const Errno EDOM = 33;      // Math argument out of domain of func
-const Errno ERANGE = 34;    // Math result not representable
+const Errno EAGAIN @if(env::DARWIN)  = 35; // Try again Macos
+const Errno EAGAIN @if(!env::DARWIN) = 11; // Try again

-$switch (env::OS_TYPE)
+const Errno ENOMEM                   = 12; // Out of memory
+const Errno EACCES                   = 13; // Permission denied
+const Errno EFAULT                   = 14; // Bad address
+const Errno ENOTBLK                  = 15; // Block device required, not on Win32
+const Errno EBUSY                    = 16; // Device or resource busy
+const Errno EEXIST                   = 17; // File exists
+const Errno EXDEV                    = 18; // Cross-device link
+const Errno ENODEV                   = 19; // No such device
+const Errno ENOTDIR                  = 20; // Not a directory
+const Errno EISDIR                   = 21; // Is a directory
+const Errno EINVAL                   = 22; // Invalid argument
+const Errno ENFILE                   = 23; // File table overflow
+const Errno EMFILE                   = 24; // Too many open files
+const Errno ENOTTY                   = 25; // Not a typewriter
+const Errno ETXTBSY                  = 26; // Text file busy, not on Win32
+const Errno EFBIG                    = 27; // File too large
+const Errno ENOSPC                   = 28; // No space left on device
+const Errno ESPIPE                   = 29; // Illegal seek
+const Errno EROFS                    = 30; // Read-only file system
+const Errno EMLINK                   = 31; // Too many links
+const Errno EPIPE                    = 32; // Broken pipe
+const Errno EDOM                     = 33; // Math argument out of domain of func
+const Errno ERANGE                   = 34; // Math result not representable

-$case MACOSX:
-const Errno EDEADLK = 11;       // Resource deadlock would occur MacOS
-const Errno ENAMETOOLONG = 63;  // File name too long MacOS
-const Errno ELOOP = 62;         // Too many symbolic links encountered
-const Errno EOVERFLOW = 84;     // Value too large for defined data type Macos
-const Errno ECONNRESET = 54;    // Connection reset by peer Macos
-const Errno ENETDOWN = 50;      // Network is down MacOS
-const Errno ENETUNREACH = 51;   // Network is unreachable MacOS
-const Errno ENETRESET = 52;     // Network dropped connection because of reset MacOS
-const Errno EOPNOTSUPP = 45;    // Operation not supported on transport endpoint
+// https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/intro.2.html
+module libc::errno @if(env::DARWIN);
+const Errno EWOULDBLOCK              = EAGAIN; // Operation would block
+const Errno EDEADLK                  = 11; // Resource deadlock would occur
+const Errno EINPROGRESS              = 36; // Operation now in progress
+const Errno EALREADY                 = 37; // Operation already in progress
+const Errno ENOTSOCK                 = 38; // Socket operation on non-socket
+const Errno EDESTADDRREQ             = 39; // Destination address required
+const Errno EMSGSIZE                 = 40; // Message too long
+const Errno EPROTOTYPE               = 41; // Protocol wrong type for socket
+const Errno ENOPROTOOPT              = 42; // Protocol not available
+const Errno EPROTONOSUPPORT          = 43; // Protocol not supported
+const Errno ESOCKTNOSUPPORT          = 44; // Socket type not supported
+const Errno ENOTSUP                  = 45; // Not supported
+const Errno EPFNOSUPPORT             = 46; // Protocol family not supported
+const Errno EAFNOSUPPORT             = 47; // Address family not supported by protocol family
+const Errno EADDRINUSE               = 48; // Address already in use
+const Errno EADDRNOTAVAIL            = 49; // Cannot assign requested address
+const Errno ENETDOWN                 = 50; // Network is down
+const Errno ENETUNREACH              = 51; // Network is unreachable
+const Errno ENETRESET                = 52; // Network dropped connection on reset
+const Errno ECONNABORTED             = 53; // Software caused connection abort
+const Errno ECONNRESET               = 54; // Connection reset by peer
+const Errno ENOBUFS                  = 55; // No buffer space available
+const Errno EISCONN                  = 56; // Socket is already connected
+const Errno ENOTCONN                 = 57; // Socket is not connected
+const Errno ESHUTDOWN                = 58; // Cannot send after socket shutdown
+const Errno ETIMEDOUT                = 60; // Operation timed out
+const Errno ECONNREFUSED             = 61; // Connection refused
+const Errno ELOOP                    = 62; // Too many levels of symbolic links
+const Errno ENAMETOOLONG             = 63; // File name too long
+const Errno EHOSTDOWN                = 64; // Host is down
+const Errno EHOSTUNREACH             = 65; // No route to host
+const Errno ENOTEMPTY                = 66; // Directory not empty
+const Errno EPROCLIM                 = 67; // Too many processes
+const Errno EUSERS                   = 68; // Too many users
+const Errno EDQUOT                   = 69; // Disc quota exceeded
+const Errno ESTALE                   = 70; // Stale NFS file handle
+const Errno EBADRPC                  = 72; // RPC struct is bad
+const Errno ERPCMISMATCH             = 73; // RPC version wrong
+const Errno EPROGUNAVAIL             = 74; // RPC prog. not avail
+const Errno EPROGMISMATCH            = 75; // Program version wrong
+const Errno EPROCUNAVAIL             = 76; // Bad procedure for program
+const Errno ENOLCK                   = 77; // No locks available
+const Errno ENOSYS                   = 78; // Function not implemented
+const Errno EFTYPE                   = 79; // Inappropriate file type or format
+const Errno EAUTH                    = 80; // Authentication error
+const Errno ENEEDAUTH                = 81; // Need authenticator
+const Errno EPWROFF                  = 82; // Device power is off
+const Errno EDEVERR                  = 83; // Device error
+const Errno EOVERFLOW                = 84; // Value too large to be stored in data type
+const Errno EBADEXEC                 = 85; // Bad executable (or shared library)
+const Errno EBADARCH                 = 86; // Bad CPU type in executable
+const Errno ESHLIBVERS               = 87; // Shared library version mismatch
+const Errno EBADMACHO                = 88; // Malformed Mach-o file
+const Errno ECANCELED                = 89; // Operation canceled
+const Errno EIDRM                    = 90; // Identifier removed
+const Errno ENOMSG                   = 91; // No message of desired type
+const Errno EILSEQ                   = 92; // Illegal byte sequence
+const Errno ENOATTR                  = 93; // Attribute not found
+const Errno EBADMSG                  = 94; // Bad message
+const Errno EMULTIHOP                = 95; // Reserved
+const Errno ENODATA                  = 96; // No message available
+const Errno ENOLINK                  = 97; // Reserved
+const Errno ENOSR                    = 98; // No STREAM resources
+const Errno ENOSTR                   = 99; // Not a STREAM
+const Errno EPROTO                   = 100; // Protocol error
+const Errno ETIME                    = 101; // STREAM ioctl() timeout
+const Errno EOPNOTSUPP               = 102; // Operation not supported on socket

-$case WIN32:
-const Errno EDEADLK = 36;       // Resource deadlock would occur Win32
-const Errno ENAMETOOLONG = 38;  // File name too long Win32
-const Errno ELOOP = 114;        // Too many symbolic links encountered
-const Errno EOVERFLOW = 132;    // Value too large for defined data type
-const Errno ENETDOWN = 116;     // Network is down
-const Errno ECONNRESET = 108;   // Connection reset by peer
-const Errno ENETUNREACH = 118;  // Network is unreachable
-const Errno ENETRESET = 117;    // Network dropped connection because of reset
-const Errno EOPNOTSUPP = 130;   // Operation not supported on transport endpoint
-
-$default:
-const Errno EDEADLK = 35;       // Resource deadlock would occur Linux (others?)
-const Errno ENAMETOOLONG = 36;  // File name too long Linux (others?)
-const Errno ELOOP = 40;         // Too many symbolic links encountered
-const Errno EOVERFLOW = 75;     // Value too large for defined data type
-const Errno ENETDOWN = 100;     // Network is down
-const Errno ECONNRESET = 104;   // Connection reset by peer
-const Errno ENETUNREACH = 101;  // Network is unreachable
-const Errno ENETRESET = 102;    // Network dropped connection because of reset
-const Errno EOPNOTSUPP = 95;    // Operation not supported on transport endpoint
-
-$endswitch
+module libc::errno @if(env::WIN32);
+const Errno EDEADLK                  = 36; // Resource deadlock would occur Win32
+const Errno ENAMETOOLONG             = 38; // File name too long Win32
+const Errno ENOTEMPTY                = 41; // Directory not empty
+const Errno ELOOP                    = 114; // Too many symbolic links encountered
+const Errno EOVERFLOW                = 132; // Value too large for defined data type
+const Errno ENETDOWN                 = 116; // Network is down
+const Errno ECONNRESET               = 108; // Connection reset by peer
+const Errno ENETUNREACH              = 118; // Network is unreachable
+const Errno ENETRESET                = 117; // Network dropped connection because of reset
+const Errno EOPNOTSUPP               = 130; // Operation not supported on transport endpoint
+const Errno ETIMEDOUT                = 138; // Connection timed out
+const Errno EALREADY                 = 103; // Operation already in progress
+const Errno EINPROGRESS              = 112; // Operation now in progress Win32
+const Errno EDQUOT                   = -122; // Quota exceeded, not in Win32
+const Errno EWOULDBLOCK              = 140; // Operation would block

+module libc::errno @if(!env::WIN32 && !env::DARWIN);
+const Errno EDEADLK                  = 35; // Resource deadlock would occur Linux (others?)
+const Errno ENAMETOOLONG             = 36; // File name too long Linux (others?)
+const Errno ENOTEMPTY                = 39; // Directory not empty
+const Errno ELOOP                    = 40; // Too many symbolic links encountered
+const Errno EWOULDBLOCK              = EAGAIN; // Operation would block
+const Errno EOVERFLOW                = 75; // Value too large for defined data type
+const Errno ENOTSOCK                 = 88; // Socket operation on non-socket
+const Errno EOPNOTSUPP               = 95; // Operation not supported on transport endpoint
+const Errno EADDRINUSE               = 98; // Address already in use
+const Errno EADDRNOTAVAIL            = 99; // Cannot assign requested address
+const Errno ENETDOWN                 = 100; // Network is down
+const Errno ENETUNREACH              = 101; // Network is unreachable
+const Errno ENETRESET                = 102; // Network dropped connection because of reset
+const Errno ECONNRESET               = 104; // Connection reset by peer
+const Errno EISCONN                  = 106; // Socket is already connected
+const Errno ETIMEDOUT                = 110; // Connection timed out
+const Errno ECONNREFUSED             = 111; // Connection refused
+const Errno EALREADY                 = 114; // Operation already in progress
+const Errno EINPROGRESS              = 115; // Operation now in progress
+const Errno EDQUOT                   = 122; // Quota exceeded


 /*
 const Errno ENOLCK = 37;  /* No record locks available */
 const Errno ENOSYS = 38;  /* Function not implemented */
-const Errno ENOTEMPTY = 39;  /* Directory not empty */

 const Errno ENOMSG = 42;  /* No message of desired type */
 const Errno EIDRM = 43;  /* Identifier removed */
@@ -515,7 +628,6 @@ const Errno ESOCKTNOSUPPORT = 94;  /* Socket type not supported */
 const Errno EPFNOSUPPORT = 96;  /* Protocol family not supported */
 const Errno EAFNOSUPPORT = 97;  /* Address family not supported by protocol */
 const Errno EADDRINUSE = 98;  /* Address already in use */
-const Errno EADDRNOTAVAIL = 99;  /* Cannot assign requested address */
 const Errno ECONNABORTED = 103; /* Software caused connection abort */
 const Errno ENOBUFS = 105; /* No buffer space available */
 const Errno EISCONN = 106; /* Transport endpoint is already connected */
@@ -527,29 +639,6 @@ const Errno EHOSTDOWN = 112; /* Host is down */
 const Errno EHOSTUNREACH = 113; /* No route to host */
 */

-$switch (env::OS_TYPE)
-
-$case MACOSX:
-const Errno ETIMEDOUT = 60;     // Connection timed out
-const Errno EINPROGRESS = 36;   // Operation now in progress MacOS
-const Errno EALREADY = 37;      // Operation already in progress MacOS
-const Errno EDQUOT = 69;        // Quota exceeded, MacOS
-const Errno EWOULDBLOCK = 35;   // Operation would block
-
-$case WIN32:
-const Errno ETIMEDOUT = 138;    // Connection timed out
-const Errno EALREADY = 103;     // Operation already in progress
-const Errno EINPROGRESS = 112;  // Operation now in progress Win32
-const Errno EDQUOT = -122;      // Quota exceeded, not in Win32
-const Errno EWOULDBLOCK = 140;  // Operation would block
-
-$default:
-const Errno ETIMEDOUT = 110;    // Connection timed out
-const Errno EALREADY = 114;     // Operation already in progress
-const Errno EINPROGRESS = 115;  // Operation now in progress
-const Errno EDQUOT = 122;       // Quota exceeded
-const Errno EWOULDBLOCK = 41;   // Operation would block
-$endswitch

 /*
 const Errno ESTALE = 116; /* Stale NFS file handle */
--- a/lib/std/libc/libc_extra.c3
+++ b/lib/std/libc/libc_extra.c3
@@ -0,0 +1,22 @@
+module libc;
+import std::time;
+
+/**
+ * @require self >= 0
+ **/
+fn TimeSpec NanoDuration.to_timespec(self) @inline
+{
+	CLong ns = (CLong)(self % 1000_000_000);
+	Time_t sec = (Time_t)(self / 1000_000_000);
+	return { .s = sec, .ns = ns };
+}
+
+/**
+ * @require self >= 0
+ **/
+fn TimeSpec Duration.to_timespec(self) @inline
+{
+	CLong ns = (CLong)(1000 * (self % time::SEC));
+	Time_t sec = (Time_t)(self / time::SEC);
+	return { .s = sec, .ns = ns };
+}
--- a/lib/std/libc/os/darwin.c3
+++ b/lib/std/libc/os/darwin.c3
@@ -0,0 +1,35 @@
+module libc @if(env::DARWIN);
+
+def Dev_t = int;
+def Mode_t = ushort;
+def Nlink_t = ushort;
+def Blkcnt_t = long;
+def Blksize_t = int;
+def Ino_t = ulong;
+
+struct Stat
+{
+	Dev_t st_dev;
+	Mode_t st_mode;
+	Nlink_t st_nlink;
+	Ino_t st_ino;
+	Uid_t st_uid;
+	Gid_t st_gid;
+	Dev_t st_rdev;
+
+	Timespec st_atimespec; // time of last access
+	Timespec st_mtimespec; // time of last data modification
+	Timespec st_ctimespec; // time of last status change
+	Timespec st_birthtimespec; // time of file creation(birth)
+	Off_t st_size; // file size, in bytes
+	Blkcnt_t st_blocks; // blocks allocated for file
+	Blksize_t st_blocksize; // optimal blocksize for I/O
+	uint st_flags; // user defined flags for file
+	uint st_gen; // file generation number
+	int st_lspare; // RESERVED
+	long[2] st_qspare; // RESERVED
+}
+
+extern fn int stat(ZString str, Stat* stat) @extern("stat64");
+
+extern fn CInt sysctl(CInt *name, CUInt namelen, void *oldp, usz *oldlenp, void *newp, usz newlen);
--- a/lib/std/libc/os/errno.c3
+++ b/lib/std/libc/os/errno.c3
@@ -1,38 +1,28 @@
 module libc::os;

+// Linux
+extern fn int* __errno_location() @if(env::LINUX);
+macro int errno() @if(env::LINUX) => *__errno_location();
+macro void errno_set(int err) @if(env::LINUX) => *(__errno_location()) = err;

-$switch
+// Darwin
+extern fn int* __error() @if(env::DARWIN);
+macro int errno() @if(env::DARWIN) => *__error();
+macro void errno_set(int err) @if(env::DARWIN) => *(__error()) = err;

-$case env::COMPILER_LIBC_AVAILABLE && env::OS_TYPE == LINUX:
-
-extern fn int* __errno_location();
-macro int errno() => *__errno_location();
-macro void errno_set(int err) => *(__errno_location()) = err;
-
-$case env::COMPILER_LIBC_AVAILABLE && env::OS_TYPE == MACOSX:
-
-extern fn int* __error();
-macro int errno() => *__error();
-macro void errno_set(int err) => *(__error()) = err;
-
-$case env::COMPILER_LIBC_AVAILABLE && env::OS_TYPE == WIN32:
-
-macro int errno()
+// Win32
+macro int errno() @if(env::WIN32)
 {
 	int holder;
 	_get_errno(&holder);
 	return holder;
 }
+macro void errno_set(int err) @if(env::WIN32) => _set_errno(err);
+extern fn void _get_errno(int* result) @if(env::WIN32);
+extern fn void _set_errno(int err) @if(env::WIN32);

-macro void errno_set(int err) => _set_errno(err);
-
-extern fn void _get_errno(int* result);
-extern fn void _set_errno(int err);
-
-$default:
-
-tlocal int _errno_c3 = 0;
-fn void errno_set(int err) => _errno_c3 = err;
-fn int errno() => _errno_c3;
-
-$endswitch
+// Default
+const ERRNO_DEFAULT @local = !env::LINUX && !env::DARWIN && !env::WIN32;
+tlocal int _errno_c3 @if(ERRNO_DEFAULT) = 0;
+fn void errno_set(int err) @if(ERRNO_DEFAULT) => _errno_c3 = err;
+fn int errno() @if(ERRNO_DEFAULT) => _errno_c3;
--- a/lib/std/libc/os/linux.c3
+++ b/lib/std/libc/os/linux.c3
@@ -0,0 +1,62 @@
+module libc @if(env::LINUX);
+
+// Checked for x86_64, this is notoriously incorrect when comparing with Rust code etc
+
+def Blksize_t = $typefrom(env::X86_64 ? long.typeid : CInt.typeid);
+def Nlink_t = $typefrom(env::X86_64 ? ulong.typeid : CUInt.typeid);
+def Blkcnt_t = long;
+def Ino_t = ulong;
+def Dev_t = ulong;
+def Mode_t = uint;
+def Ino64_t = ulong;
+def Blkcnt64_t = long;
+
+struct Stat @if(env::X86_64)
+{
+	Dev_t st_dev;
+	Ino_t st_ino;
+	Nlink_t st_nlink;
+	Mode_t st_mode;
+	Uid_t st_uid;
+	Gid_t st_gid;
+	CInt __pad0;
+	Dev_t st_rdev;
+	Off_t st_size;
+	Blksize_t st_blksize;
+	Blkcnt_t st_blocks;
+	Time_t st_atime;
+	long st_atime_nsec;
+	Time_t st_mtime;
+	long st_mtime_nsec;
+	Time_t st_ctime;
+	long st_ctime_nsec;
+	long[3] __unused;
+}
+
+struct Stat @if(!env::X86_64)
+{
+	Dev_t st_dev;
+	Ino_t st_ino;
+	Mode_t st_mode;
+	Nlink_t st_nlink;
+	Uid_t st_uid;
+	Gid_t st_gid;
+	Dev_t st_rdev;
+	CInt __pad1;
+	Off_t st_size;
+	Blksize_t st_blksize;
+	CInt __pad2;
+	Blkcnt_t st_blocks;
+	Time_t st_atime;
+	long st_atime_nsec;
+	Time_t st_mtime;
+	long st_mtime_nsec;
+	Time_t st_ctime;
+	long st_ctime_nsec;
+	CInt[2] __unused;
+}
+
+extern fn CInt stat(ZString path, Stat* stat);
+
+extern fn CInt get_nprocs();
+extern fn CInt get_nprocs_conf();
--- a/lib/std/libc/os/posix.c3
+++ b/lib/std/libc/os/posix.c3
@@ -0,0 +1,55 @@
+module libc @if(env::POSIX);
+
+
+extern fn void* dlopen(ZString path, int flags);
+extern fn CInt dlclose(void*);
+extern fn void* dlsym(void* handle, ZString symbol);
+
+const int RTLD_LAZY = 0x1;
+const int RTLD_NOW = 0x2;
+const int RTLD_LOCAL = 0x4;
+const int RTLD_GLOBAL = 0x8;
+
+def Pid_t = int;
+def Uid_t = uint;
+def Gid_t = uint;
+
+const CUInt SA_ONSTACK       = env::LINUX ? 0x08000000 : 0x0001;
+const CUInt SA_RESTART       = env::LINUX ? 0x10000000 : 0x0002;
+const CUInt SA_RESETHAND     = env::LINUX ? 0x80000000 : 0x0004;
+const CUInt SA_SIGINFO       = env::LINUX ? 0x00000004 : 0x0040;
+
+def Sigset_t = uint @if(!env::LINUX);
+def Sigset_t = ulong[16] @if(env::LINUX);
+def SigActionFunction =  fn void(CInt, void*, void*);
+
+struct Sigaction
+{
+	union
+    {
+    	SignalFunction      sa_handler;
+    	SigActionFunction   sa_sigaction;
+    }
+	CInt                    sa_flags @if(env::FREEBSD);
+	Sigset_t                sa_mask; // 128
+	CInt                    sa_flags @if(!env::FREEBSD);
+	void*                   sa_restorer @if(env::LINUX);
+}
+
+struct Stack_t
+{
+	void*   ss_sp;
+	struct @if(!env::LINUX)
+	{
+		usz     ss_size;
+		CInt    ss_flags;
+	}
+	struct @if(env::LINUX)
+	{
+		CInt    ss_flags;
+		usz     ss_size;
+	}
+}
+
+extern fn CInt sigaltstack(Stack_t* ss, Stack_t* old_ss);
+extern fn CInt sigaction(CInt signum, Sigaction *action, Sigaction *oldaction);
--- a/lib/std/libc/os/win32.c3
+++ b/lib/std/libc/os/win32.c3
@@ -0,0 +1,51 @@
+module libc @if(env::WIN32);
+
+
+extern fn CFile __acrt_iob_func(CInt c);
+extern fn CInt _close(Fd fd); def close = _close;
+extern fn double _difftime64(Time_t time1, Time_t time2); def difftime = _difftime64;
+extern fn CFile _fdopen(Fd fd, ZString mode); def fdopen = _fdopen;
+extern fn CInt _fileno(CFile stream); def fileno = _fileno;
+extern fn CInt _fseeki64(CFile, long, int); def fseek = _fseeki64;
+extern fn CLong _ftelli64(CFile); def ftell = _ftelli64;
+extern fn Errno _get_timezone(CLong *timezone);
+extern fn Tm* _gmtime64_s(Tm* buf, Time_t *timer);
+extern fn Tm* _localtime64_s(Tm* buf, Time_t *timer);
+extern fn Time_t _mkgmtime64(Tm* timeptr); def timegm = _mkgmtime64;
+extern fn Time_t _mktime64(Tm *timeptr); def mktime = _mktime64;
+extern fn usz _msize(void* ptr);
+extern fn CInt _read(Fd fd, void* buffer, CUInt buffer_size);
+extern fn CInt _setjmp(void* frameptr, JmpBuf* buffer) @if(env::WIN32);
+extern fn CFile _wfopen(WString, WString);
+extern fn CFile _wfreopen(WString, WString, CFile);
+extern fn CInt _write(Fd fd, void* buffer, CUInt count);
+extern fn CInt _wremove(WString);
+
+struct SystemInfo
+{
+	union {
+		uint dwOemId;
+		struct {
+			ushort wProcessorArchitecture;
+			ushort wReserved;
+		}
+	}
+	uint     dwPageSize;
+	void*    lpMinimumApplicationAddress;
+	void*    lpMaximumApplicationAddress;
+	usz      dwActiveProcessorMask;
+	uint     dwNumberOfProcessors;
+	uint     dwProcessorType;
+	uint     dwAllocationGranularity;
+	ushort   wProcessorLevel;
+	ushort   wProcessorRevision;
+}
+
+extern fn CInt get_system_info(SystemInfo*) @extern("GetSystemInfo");
+
+// Aliases to simplify libc use
+macro Tm* localtime_r(Time_t* timer, Tm* buf) => _localtime64_s(buf, timer);
+macro CInt setjmp(JmpBuf* buffer) => _setjmp($$frameaddress(0), buffer);
+macro Tm* gmtime_r(Time_t* timer, Tm* buf) => _gmtime64_s(buf, timer);
+macro isz read(Fd fd, void* buffer, usz buffer_size) => _read(fd, buffer, (CUInt)buffer_size);
+macro isz write(Fd fd, void* buffer, usz count) => _write(fd, buffer, (CUInt)count);
--- a/Show More
+++ b/Show More