From 6ab7198f2f2aff6b2941bfc6d22f80e2a7576df7 Mon Sep 17 00:00:00 2001
From: Christoffer Lerno <christoffer@aegik.com>
Date: Thu, 21 Aug 2025 02:57:17 +0200
Subject: [PATCH] - Added `AsciiCharset` for matching ascii characters quickly.
 - Added `String.trim_charset`.

---
 lib/std/core/ascii.c3  | 24 ++++++++++++++++++++++++
 lib/std/core/string.c3 | 20 ++++++++++++++++++--
 releasenotes.md        |  2 ++
 3 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/lib/std/core/ascii.c3 b/lib/std/core/ascii.c3
index 68db253af..c67fc1620 100644
--- a/lib/std/core/ascii.c3
+++ b/lib/std/core/ascii.c3
@@ -112,3 +112,27 @@ const char[256] HEX_VALUE = {
 const char[256] TO_UPPER @private = { ['a'..'z'] = 'a' - 'A' };
 const char[256] TO_LOWER @private  = { ['A'..'Z'] = 'a' - 'A' };
 
+typedef AsciiCharset = uint128;
+
+macro AsciiCharset @create_set(String $string) @const
+{
+	AsciiCharset $set;
+	$foreach $c : $string:
+		$set |= 1ULL << $c;
+	$endforeach
+	return $set;
+}
+
+fn AsciiCharset create_set(String string)
+{
+	AsciiCharset set;
+	foreach (c : string) set |= (AsciiCharset)1ULL << c;
+	return set;
+}
+
+macro bool AsciiCharset.contains(set, char c) => !!(c < 128) & !!(set & (AsciiCharset)(1ULL << c));
+
+const AsciiCharset WHITESPACE_SET = @create_set("\t\n\v\f\r ");
+const AsciiCharset NUMBER_SET = @create_set("0123456789");
+
+
diff --git a/lib/std/core/string.c3 b/lib/std/core/string.c3
index 4724c5569..bb309e2c4 100644
--- a/lib/std/core/string.c3
+++ b/lib/std/core/string.c3
@@ -1,6 +1,5 @@
 module std::core::string;
-import std::io;
-import std::core::mem::allocator;
+import std::io, std::ascii;
 
 
 typedef String @if(!$defined(String)) = inline char[];
@@ -219,6 +218,23 @@ fn String String.trim(self, String to_trim = "\t\n\r ")
     return self.trim_left(to_trim).trim_right(to_trim);
 }
 
+<*
+ Remove characters from the front and end of a string.
+
+ @param [in] self : `The string to trim`
+ @param to_trim : `The set of characters to trim, defaults to whitespace`
+ @pure
+ @return `a substring of the string passed in`
+*>
+fn String String.trim_charset(self, AsciiCharset to_trim = ascii::WHITESPACE_SET)
+{
+	usz start = 0;
+	usz len = self.len;
+	while (start < len && to_trim.contains(self[start])) start++;
+	while (len > start && to_trim.contains(self[len - 1])) len--;
+    return self[start..len - 1];
+}
+
 <*
  Remove characters from the front of a string.
 
diff --git a/releasenotes.md b/releasenotes.md
index e58c39bd7..7c21e3bfd 100644
--- a/releasenotes.md
+++ b/releasenotes.md
@@ -72,6 +72,8 @@
 - Added `HashSet.values` and `String.contains_char` #2386
 - Added `&[]` overload to HashMap.
 - Deprecated `PollSubscribes` and `PollEvents` in favour of `PollSubscribe` and `PollEvent` and made them const enums.
+- Added `AsciiCharset` for matching ascii characters quickly.
+- Added `String.trim_charset`.
 
 ## 0.7.4 Change list