peg を Homebrew でインストール

プロジェクトリンク

• ホームページ

コマンドとエイリアス

• leg
• peg

プロジェクトの歴史

Ian Piumarta's official page lists peg/leg as tools for generating recursive-descent parsers from Parsing Expression Grammars. The first public release in the official version history is 0.1.1 on 2007-05-15.

The manual page explains that peg reads grammar files or standard input and generates C source defining `yyparse()`, while leg uses a syntax intended to make it attractive to users familiar with lex and yacc workflows.

The official version history shows steady maintenance through 0.1.19 stable in 2023, including reentrant parsing support, error actions, UTF-8 fixes, C++ support improvements, and Windows/Mac build files.

採用の歴史

peg/leg spread through Unix-like package managers as a small C parser-generation tool: the input metadata lists Homebrew, Debian, Ubuntu, Arch, MacPorts, Nix, Alpine, and openSUSE package names.

Its niche is smaller than yacc-family tools, but it remains useful where a project wants PEG-style ordered choice, unlimited backtracking, and combined scanning and parsing in generated C.

使われ方

Typical use is to run `peg` or `leg` over a grammar file and compile or include the generated C source in a client program.

The official manual documents options such as `-o` for output file selection, `-P` for suppressing `#line` directives, `-v` for verbose mode, and `-V` for version output.

パッケージ好きにとっての重要性

peg/leg is package-manager-friendly because it is a compact C command-line tool with a stable manual page, source tarballs, and a long version history.

For package nerds it is also a useful contrast with lex/yacc: a small PEG-based generator that produces embeddable C parsers without requiring a larger parser framework.

タイムライン

• 2007-05-15: First public release, 0.1.1.
• 2013-06-03: 0.1.11 added error actions, C++ support improvements, and Win32/Mac build files.
• 2016-07-22: 0.1.18 added the `-P` option to disable `#line` directives.
• 2023-03-06: 0.1.19 stable added experimental re-entrant parsing through `yyparsefrom_r()`.
• 2023-11-19: 0.1.20 development version listed with experimental inline-action variables and semantic values.

Related projects

• Bryan Ford's 2004 Parsing Expression Grammars paper is the formal grammar reference cited by the official page.
• lex and yacc are the comparison point used by the official page and manual.

ソース

• https://www.piumarta.com/software/peg
• https://www.piumarta.com/software/peg/peg.1.html
• source_facts.package-manager