maciejhirsz/logos

Health v2 · maintenance only

Adoption not part of the score

3550 stars · 165 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded

Logos is a Rust lexer generator library that derives fast tokenizers from enum definitions using token and regex attributes. It combines all token patterns into a single deterministic finite automaton optimized at compile time with lookup and jump tables.

Use cases

• generate a lexer for a custom programming language in rust
• tokenize source code faster than a hand-written lexer
• build a tokenizer from regex patterns with a derive macro
• lex large inputs at gigabyte-per-second throughput
• write a no_std compatible tokenizer for embedded rust
• feed tokens into a hand-written parser

When to choose

• you are writing a compiler, interpreter, or parser in Rust and need a fast lexer
• you want compile-time generated state machines instead of runtime regex matching
• you need no_std support or minimal backtracking-free tokenization

When to avoid

• you need a full parser with grammar rules, not just tokenization
• you are not working in Rust
• you need dynamic or runtime-configurable token definitions

Facets

library · maturity stable

parser compiler developer-tools parsers programming-languages developer-tools rust cross-platform lexer-generator tokenizer lexical-analysis derive-macro no-std finite-state-machine compile-time-codegen

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