# pest-parser/pest

The Elegant Parser

Repository: https://github.com/pest-parser/pest
Canonical: https://ross.abutalabs.com/products/pest-parser-pest
Homepage: https://pest.rs
Language: Rust
License: Apache-2.0
License Family: permissive
Topics: peg, rust, parsing
Last push: 2026-08-20T00:58:02+00:00

## Health v2 (maintenance only)
Score: 94/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 98, release rhythm 85, longevity 100
- inputs: {"age_days": 3783, "days_push": 14, "days_rel": 20, "gap_med": 45.5, "n_releases_24m": 15}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 5384, forks 304 (observed 2026-08-28T04:09:16.272397+00:00)

## What it is
pest is a general-purpose parser library for Rust based on parsing expression grammars (PEG). Grammars are defined in separate .pest files, and the library generates parsers with automatic, meaningful error reporting.

## Use cases
- parse a custom DSL in Rust
- write a PEG grammar for a config file format
- build a parser for a programming or markup language
- replace hand-written parsers with grammar-based ones
- get meaningful error messages when parsing fails
- parse structured text like identifiers, expressions, or logs

## When to choose
- you are writing Rust and need a parser for a text format or language
- you want grammars kept separate from procedural code
- you need good error reporting out of the box
- you want correctness guarantees from a declarative grammar

## When to avoid
- you need a hand-tuned parser faster than nom or serde-level performance
- you need context-sensitive parsing beyond PEG expressivity
- you are not working in Rust

## Facets
- artifact type: library
- maturity: stable
- function: parser
- domain: parsers, programming-languages, developer-tools
- platform: rust
- tags: peg, grammar, parser-generator, parser-combinators, error-reporting

## Member repositories
- pest-parser/pest (main) score 94

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:16.272397+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 2026-08-29T17:58:26.115358+00:00, confidence not recorded.
  - readme: https://github.com/pest-parser/pest (fetched 2026-08-28T04:09:16.272397+00:00, sha a9ed0d1aedd0)
  - homepage: https://pest.rs (fetched 2026-08-29T08:52:47.156790+00:00, sha c5a091efe0ac)
  - registry_crates: https://crates.io/api/v1/crates/pest (fetched 2026-08-29T08:52:47.165848+00:00, sha d4885a711b73)
- Data as of 2026-08-30T08:39:29.467469+00:00.