# kkos/oniguruma

regular expression library

Repository: https://github.com/kkos/oniguruma
Canonical: https://ross.abutalabs.com/products/oniguruma
Language: C
License: NOASSERTION
License Family: other
Topics: regular-expression, regexp, c
Archived: true
Last push: 2025-04-24T12:42:35+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 18, release rhythm 8, longevity 100
- inputs: {"age_days": 4069, "days_push": 496, "days_rel": 610, "gap_med": null, "n_releases_24m": 1}
- flags: archived, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2523, forks 350 (observed 2026-08-28T04:06:58.442585+00:00)

## What it is
Oniguruma is a flexible C regular expression library supporting many regex syntaxes and a wide range of character encodings, historically used by Ruby and other tools. The project officially ended on April 24, 2025, and is no longer maintained.

## Use cases
- embed a regex engine in a C or C++ application
- match text with Ruby-style regular expressions
- handle regexes across many character encodings like EUC-JP, Shift_JIS, and GB18030
- use Unicode properties like \pL in pattern matching
- replace POSIX regex with a more feature-rich engine

## When to choose
- you need a mature, battle-tested regex engine in C with broad encoding support
- you must match Ruby or Oniguruma-specific regex syntax
- you are pinned to a legacy codebase already using Oniguruma

## When to avoid
- starting a new project, since the project ended in April 2025 and receives no security fixes
- you need long-term maintenance and CVE patching
- a modern alternative like PCRE2 or Rust regex fits your needs

## Facets
- artifact type: library
- maturity: abandoned
- function: parser, nlp
- domain: parsers, developer-tools
- platform: c, cross-platform, cli
- tags: regular-expressions, regex-engine, text-processing, unicode, character-encoding, ruby-regex, end-of-life, natural-language-processing

## Member repositories
- kkos/oniguruma (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:58.442585+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T02:25:46.936158+00:00, confidence not recorded.
  - readme: https://github.com/kkos/oniguruma (fetched 2026-08-28T04:06:58.442585+00:00, sha ef4e77788077)
- Data as of 2026-08-30T08:39:29.467469+00:00.