C3 Language

C3 is a C-like language trying to be "an incremental improvement over C" rather than a whole new language. C3 owes a lot to the ideas of the C2 language: to iterate on top of C without trying to be a whole new language.

C3 tries to be an alternative in the the C/C++ niche: fast and close to the metal.

Design Principles

• Procedural "get things done"-type of language.
• Try to stay close to C - only change where truly needed.
• C ABI compatibility and excellent C integration.
• Learning C3 should be easy for a C programmer.
• Data is inert.
• Avoid "big ideas" & the "more is better" fallacy.
• Introduce some higher level conveniences where the value is great.

Example code

module hello_world;
import std::io;

func void main()
{
   io::printf("Hello, world!\n");
}

In what ways do C3 differ from C?

• No mandatory header files
• New semantic macro system
• Generic modules
• Module based
• Subarrays (slices) and vararrays built in
• Compile time reflection
• Enhanced compile time execution
• "Result" based zero overhead error handling
• Defer
• Value methods
• Associated enum data
• Built in strings
• No preprocessor
• Undefined behaviour trapped on debug by default
• Optional pre and post conditions

Current status

It's possible to try out the current C3 compiler in the browser: https://ide.judge0.com/?1EFo – this is courtesy of the developer of Judge0.

Design work is still being done in the design draft here: https://c3lang.github.io/c3docs/. If you have any suggestions, send a mail to christoffer@aegik.com, [file an issue] (https://github.com/c3lang/c3c/issues) or discuss C3 on its dedicated Discord: https://discord.gg/qN76R87 you are also welcome to discuss in the C3 channel on the r/ProgrammingLanguages Discord: https://discord.gg/cfu4wdk

Todo / done

• For/while/do
• if/ternary
• Structs
• Union
• Enums
• Value methods
• Compound literals
• Designated initalizers
• Slicing syntax
• Arrays and subarrays
• Modules
• $unreachable
• Compile time assert with $assert
• Compiler guiding assert
• C code calling by declaring methods extern
• Compile time variables
• Basic macros
• 4cc, 8cc, 2cc
• Enum type inference in switch/assignment
• Integer type inference
• Error type
• Failable error handling
• try for conditional execution
• catch for error handling
• Implicit unwrap after catch
• sizeof
• typeof
• 2s complement wrapping operators
• Labelled break / continue
• next statement
• Expression blocks
• Do-without-while
• Foreach statement
• All attributes
• Associative array literals
• CT type constants
• Reflection methods
• Anonymous structs
• Distinct types
• LTO/ThinLTO setup
• Built-in linking
• global / shared for globals
• Complex macros
• CT only macros evaluating to constants
• Escape macros
• Implicit capturing macros
• Trailing body macros
• Subarray initializers
• slice initializers e.g. { [1..2] = 2 }
• Bitstructs
• asm section
• $switch
• $for
• Pre-post conditions
• Stdlib inclusion
• Generic modules
• String functions
• Vararrays e.g. int[*]
• Compile time incremental arrays
• [-] Complete C ABI conformance in progress
• Generic functions
• [-] Debug info in progress
• Simd vectors
• Complex types

What can you help with?

• If you wish to contribute with ideas, please file issues on the c3docs: https://github.com/c3lang/c3docs instead of the compiler.
• Discuss the language on discord to help iron out syntax.
• Stdlib work will soon start, do you want to help out building the C3 std lib?
• Do you want to do real compiler work? Everyone is welcome to contribute.