# jzimmerman/langcc

langcc: A Next-Generation Compiler Compiler

Repository: https://github.com/jzimmerman/langcc
Canonical: https://ross.abutalabs.com/products/langcc
Homepage: https://langcc.io
Language: C++
License: Apache-2.0
License Family: permissive
Last push: 2022-12-21T19:13:42+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 1444, "days_push": 1351, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1728, forks 61 (observed 2026-08-28T04:05:28.476831+00:00)

## What it is
langcc is a next-generation compiler compiler that generates efficient linear-time parsers and full compiler frontends (AST definitions, traversals, pretty-printing) from a single declarative .lang grammar file. It extends canonical LR parsing with recursive-descent actions, attribute constraints, and continuation-passing style transformations, and ships with a companion datatype compiler (datacc) for C++ algebraic datatypes.

## Use cases
- generate a parser for a new programming language
- replace lex and yacc with a more powerful grammar tool
- generate AST definitions and traversals from a grammar spec
- debug LR grammar conflicts with concrete example inputs
- generate C++ algebraic datatypes including sum types
- prototype compiler frontends for research languages

## When to choose
- building a compiler or interpreter frontend in C++
- your grammar is beyond LR(1) and yacc rejects it
- you want declarative grammar specs without embedded C++ actions
- you need fast, linear-time parsers for industrial languages

## When to avoid
- you need a parser in a language other than C++
- you need a mature ecosystem with active maintenance and community support
- you only need a simple regex-based lexer
- you target dynamic or runtime-extensible grammars

## Facets
- artifact type: cli-tool
- maturity: stable
- function: parser, compiler, developer-tools
- domain: compilers, programming-languages, parsers, developer-tools
- platform: cpp, cli
- tags: compiler-compiler, lr-parsing, lex-yacc-replacement, ast-generation, grammar-specification, datatypes, self-hosting, code-generation, linux, macos

## Member repositories
- jzimmerman/langcc (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:28.476831+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 2026-08-30T03:32:09.737510+00:00, confidence not recorded.
  - readme: https://github.com/jzimmerman/langcc (fetched 2026-08-28T04:05:28.476831+00:00, sha cf18b5472403)
  - homepage: https://langcc.io (fetched 2026-08-29T11:08:49.448520+00:00, sha 926d76a61d98)
- Data as of 2026-08-30T08:39:29.467469+00:00.