rust-lang/regex

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An implementation of regular expressions for Rust. This implementation uses finite automata and guarantees linear time matching on all inputs.

Stars: 4k
Forks: 534
Open beginner issues: 0
Indexed issues: 49

Dominant language: Rust
License: Apache-2.0
Last GitHub push: Aug 10, 2026
Latest indexed: Sep 19, 2026
Contributing guide: No contributing guide
Code of conduct: No code of conduct
Beginner labels: help wanted
PR merge metrics: No merged PRs in 30d

Beginner friendly Everything

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49 open issues indexed

bug(syntax): `Ord` on `ast::Position` is inconsistent with `Eq` Open

Difficulty 2/5 1-3 hours Newbie friendliness 85/100

rust-lang/regex#1393 · Opened Sep 8, 2026
bug(syntax): Panic when `Parser` is used twice Open

Difficulty 2/5 1-3 hours Newbie friendliness 84/100

rust-lang/regex#1392 · Opened Sep 8, 2026
Feature request: sticky matching without relying on slicing, so that `Match` range corresponds to unsliced string Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

rust-lang/regex#1390 · Opened Aug 27, 2026
Significant memory usage regression in regex-automata 0.4.17 Open

Difficulty 3/5 1-2 days Newbie friendliness 65/100

rust-lang/regex#1389 · 3 reactions · Opened Aug 24, 2026
Unicode 17? Open

Difficulty 4/5 3-5 days Newbie friendliness 62/100

rust-lang/regex#1387 · 1 comment · Opened Aug 11, 2026
Incorrect alternation chosen when .*.* occurs in pattern Open

Difficulty 4/5 3-5 days Newbie friendliness 55/100

rust-lang/regex#1360 · 1 comment · 1 reaction · Opened Jun 3, 2026
regex and regex_lite disagree on whether repetition operators associate with flag-setters Open

Difficulty 3/5 1-2 days Newbie friendliness 55/100

rust-lang/regex#1359 · 1 comment · Opened Jun 3, 2026
'Overlapping' empty match suppression algorithm hides real non-empty matches Open

Difficulty 3/5 1-2 days Newbie friendliness 55/100

rust-lang/regex#1358 · 1 comment · 1 reaction · Opened Jun 2, 2026
regex and regex_lite disagree on lazy empty matches Open

Difficulty 4/5 3-5 days Newbie friendliness 45/100

rust-lang/regex#1357 · 4 comments · Opened Jun 2, 2026
Provide an API for comparing the equivalence of two `Regex` values (while permitting false negatives) Open

enhancement question

Difficulty 5/5 Over a week Newbie friendliness 45/100

rust-lang/regex#1349 · 4 comments · Opened May 18, 2026
Maybe a way to reduce binary size cost by CASE_FOLDING_SIMPLE Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

rust-lang/regex#1347 · Opened May 14, 2026
`BoundedBacktracker::is_match` panics on empty haystack when `max_haystack_len()` saturates to 0 Open

Difficulty 3/5 1-2 days Newbie friendliness 55/100

rust-lang/regex#1344 · Opened Apr 29, 2026
Are `::bytes::RegexSet` and `::bytes::Regex` coming to `regex-lite`? Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

rust-lang/regex#1338 · 1 reaction · Opened Mar 17, 2026
Question: Do PCRE2 leftmost-first semantics include capture group positions? Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

rust-lang/regex#1336 · Opened Mar 11, 2026
`regex_syntax::escape()` does not escape whitespace Open

question

Difficulty 2/5 1-3 hours Newbie friendliness 45/100

rust-lang/regex#1323 · 9 comments · 1 reaction · Opened Jan 14, 2026
De/serializing one-pass DFAs Open

enhancement question

Difficulty 5/5 Over a week Newbie friendliness 25/100

rust-lang/regex#1322 · 1 comment · Opened Jan 1, 2026
Compiling some unicode regexes is 2.5x slower Open

enhancement question

Difficulty 4/5 3-5 days Newbie friendliness 45/100

rust-lang/regex#1316 · 2 comments · Opened Nov 14, 2025
a prefilter should only be constructed if we know we'll use it Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

rust-lang/regex#1311 · Opened Oct 30, 2025
fix runaway generation of literals for case insensitive regexes Open

bug

Difficulty 5/5 Over a week Newbie friendliness 20/100

rust-lang/regex#1310 · Opened Oct 30, 2025
investigate optimizations for patterns like `(?m)^\w+$` Open

enhancement

Difficulty 5/5 Over a week Newbie friendliness 35/100

rust-lang/regex#1301 · Opened Oct 7, 2025
Feature: Iterator over matching and non-matching parts of a haystack Open

Difficulty 4/5 3-5 days Newbie friendliness 38/100

rust-lang/regex#1296 · 1 comment · Opened Sep 22, 2025
Linear Time Lookaround Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

rust-lang/regex#1273 · 4 comments · 3 reactions · Opened Jun 26, 2025
regex-syntax: some way to retain the AST Span of some punctuation marks? Open

Difficulty 5/5 Over a week Newbie friendliness 32/100

rust-lang/regex#1271 · 2 comments · Opened Jun 13, 2025
Detected assertion fails and index out of bounds panic during fuzz testing Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rust-lang/regex#1265 · Opened May 13, 2025
feature request: Add `impl TryFrom<Arc<str>> for Regex` Open

enhancement

Difficulty 2/5 1-3 hours Newbie friendliness 35/100

rust-lang/regex#1257 · 7 comments · Opened Apr 4, 2025
Add `regex::Regex::get_config` Open

question

Difficulty 2/5 1-3 hours Newbie friendliness 48/100

rust-lang/regex#1250 · 6 comments · Opened Jan 16, 2025
doc clarification: confusing match behavior for non-existent ASCII character classes Open

documentation

Difficulty 2/5 1-3 hours Newbie friendliness 35/100

rust-lang/regex#1234 · 1 comment · Opened Oct 27, 2024
remove trait implementation of `std::str::pattern::Pattern` Open

plan question

Difficulty 5/5 Over a week Newbie friendliness 20/100

rust-lang/regex#1233 · 1 comment · Opened Oct 24, 2024
calling `caputres_iter` in an `async` function may cause memory leak Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

rust-lang/regex#1214 · 21 comments · Opened Jul 26, 2024
regex-lite with a &[u8] haystack Open

enhancement

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rust-lang/regex#1196 · 2 comments · 4 reactions · Opened May 18, 2024
Errors when running quickstart from docs Open

documentation

Difficulty 2/5 1-3 hours Newbie friendliness 48/100

rust-lang/regex#1183 · 2 comments · Opened Apr 18, 2024
`meta::Cache::reset` can panic Open

bug

Difficulty 3/5 1-2 days Newbie friendliness 45/100

rust-lang/regex#1155 · Opened Jan 24, 2024
UnicodeSetsMode support (`v` flag mode, `\q`) Open

question

Difficulty 5/5 Over a week Newbie friendliness 35/100

rust-lang/regex#1142 · 9 comments · Opened Dec 25, 2023
`regex-syntax` error messages highlight incorrect characters/not handling graphemes correctly Open

enhancement help wanted

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rust-lang/regex#1132 · 4 comments · Opened Nov 30, 2023
regex-lite: make the std feature optional Open

enhancement

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rust-lang/regex#1122 · 9 comments · 3 reactions · Opened Nov 3, 2023
investigate skipping reverse NFA compilation if regex is anchored Open

enhancement help wanted

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rust-lang/regex#1097 · 1 comment · Opened Oct 6, 2023
FST transducer support Open

enhancement

Difficulty 5/5 Over a week Newbie friendliness 25/100

rust-lang/regex#1087 · 9 comments · 1 reaction · Opened Sep 8, 2023
Add differential fuzzing between different regex engines Open

enhancement

Difficulty 5/5 Over a week Newbie friendliness 20/100

rust-lang/regex#1003 · Opened Jun 2, 2023
`regex-syntax` Hir should merge alternation of Class & Literal into Class Open

enhancement help wanted

Difficulty 3/5 1-2 days Newbie friendliness 42/100

rust-lang/regex#1001 · 1 comment · Opened May 29, 2023
add WASM testing to CI Open

enhancement help wanted

Difficulty 4/5 3-5 days Newbie friendliness 25/100

rust-lang/regex#983 · 6 reactions · Opened Apr 21, 2023
API to get size of compiled regex Open

enhancement question

Difficulty 4/5 3-5 days Newbie friendliness 45/100

rust-lang/regex#943 · 8 comments · Opened Jan 6, 2023
implement regex engine for handling regexes like `^(<match at most one codepoint>){m,n}$` Open

enhancement help wanted question

Difficulty 5/5 Over a week Newbie friendliness 25/100

rust-lang/regex#802 · 3 comments · 1 reaction · Opened Aug 19, 2021
the Replacer trait should be parameterized over a lifetime Open

enhancement regex2

Difficulty 5/5 Over a week Newbie friendliness 30/100

rust-lang/regex#777 · 1 comment · 4 reactions · Opened May 5, 2021
test marker traits more rigorously on public API types Open

enhancement

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rust-lang/regex#756 · 17 comments · Opened Apr 8, 2021
Introduce split_inclusive to API Open

enhancement

Difficulty 5/5 Over a week Newbie friendliness 35/100

rust-lang/regex#681 · 8 comments · 3 reactions · Opened May 19, 2020
release regex-capi 1.0 Open

enhancement

Difficulty 5/5 Over a week Newbie friendliness 25/100

rust-lang/regex#574 · 3 comments · Opened Apr 8, 2019
Add a document that describes differences with other regex engines Open

documentation enhancement

Difficulty 5/5 Over a week Newbie friendliness 30/100

rust-lang/regex#497 · 2 comments · 1 reaction · Opened Jul 3, 2018
execute a regex on text streams Open

enhancement question

Difficulty 5/5 Over a week Newbie friendliness 25/100

rust-lang/regex#425 · 104 comments · 41 reactions · Opened Dec 3, 2017
Underscore in replacement string treated as backspace Open

enhancement regex2

Difficulty 3/5 1-2 days Newbie friendliness 35/100

rust-lang/regex#69 · 9 comments · 1 reaction · Opened Apr 13, 2015

rust-lang/regex

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