From 157c1db358bf31dc9a409a1a9d9b5d4e57936f31 Mon Sep 17 00:00:00 2001
From: John Turner <jturner.usa@gmail.com>
Date: Sun, 26 Oct 2025 01:10:37 -0400
Subject: impl Regex parser

---
 Cargo.lock | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 Cargo.toml |  5 ++++-
 src/lib.rs | 42 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 93 insertions(+), 1 deletion(-)

diff --git a/Cargo.lock b/Cargo.lock
index f8fafb9..5ab13d1 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,6 +2,53 @@
 # It is not intended for manual editing.
 version = 4
 
+[[package]]
+name = "aho-corasick"
+version = "1.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e60d3430d3a69478ad0993f19238d2df97c507009a52b3c10addcd7f6bcb916"
+dependencies = [
+ "memchr",
+]
+
+[[package]]
+name = "memchr"
+version = "2.7.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f52b00d39961fc5b2736ea853c9cc86238e165017a493d1d5c8eac6bdc4cc273"
+
 [[package]]
 name = "mon"
 version = "0.1.0"
+dependencies = [
+ "regex",
+]
+
+[[package]]
+name = "regex"
+version = "1.12.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "843bc0191f75f3e22651ae5f1e72939ab2f72a4bc30fa80a066bd66edefc24d4"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5276caf25ac86c8d810222b3dbb938e512c55c6831a10f3e6ed1c93b84041f1c"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a2d987857b319362043e95f5353c0535c1f58eec5336fdfcf626430af7def58"
diff --git a/Cargo.toml b/Cargo.toml
index e265454..dc005d8 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,4 +1,7 @@
 [package]
 name = "mon"
 version = "0.1.0"
-edition = "2024"
\ No newline at end of file
+edition = "2024"
+
+[dependencies]
+regex = "1.12.2"
\ No newline at end of file
diff --git a/src/lib.rs b/src/lib.rs
index 930acfe..050ed52 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1002,6 +1002,35 @@ where
     take_while1(r#if(|c: &I::Item| c.is_whitespace()))
 }
 
+pub mod str {
+
+    use super::*;
+
+    struct Regex(regex::Regex);
+
+    impl<'a> Parser<&'a str> for Regex {
+        type Output = &'a str;
+
+        fn run<OM: Mode, EM: Mode, Tracer: Trace<&'a str>>(
+            &self,
+            it: InputIter<&'a str>,
+        ) -> ParserResult<&'a str, Self::Output, OM, EM> {
+            match self.0.find(it.rest()) {
+                Some(m) => {
+                    let output = OM::bind(|| it.rest().slice(m.range()));
+                    let (rest, _) = take(m.end()).parse(it).unwrap();
+                    Ok((rest, output))
+                }
+                None => return Err(EM::bind(|| it.clone())),
+            }
+        }
+    }
+
+    pub fn regex<'a>(pattern: &'a str) -> impl Parser<&'a str, Output = &'a str> {
+        Regex(regex::Regex::new(pattern).unwrap())
+    }
+}
+
 #[cfg(test)]
 mod test {
     use super::*;
@@ -1016,4 +1045,17 @@ mod test {
             .check_finished(it)
             .unwrap();
     }
+
+    #[test]
+    fn test_regex_parser() {
+        let it = InputIter::new("abc 123");
+
+        match crate::str::regex("[abc]+").parse(it) {
+            Ok((rest, output)) => {
+                assert_eq!(output, "abc");
+                assert_eq!(rest.rest(), " 123");
+            }
+            _ => panic!(),
+        }
+    }
 }
-- 
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