This is a static archive of the Python wiki, which was retired in February 2026 due to lack of usage and the resources necessary to serve it — predominately to bots, crawlers, and LLM companies.
Pages are preserved as they were at the time of archival. For current information, please visit python.org.
If a change to this archive is absolutely needed, requests can be made via the infrastructure@python.org mailing list.

Grako (for grammar compiler) is a tool that takes grammars in a variation of EBNF as input, and outputs memoizing (Packrat) PEG parsers in Python.

Grako is different from other PEG parser generators in that the generated parsers use Python's very efficient exception-handling system to backtrack. Grako generated parsers simply assert what must be parsed; there are no complicated if-then-else sequences for decision making or backtracking.

Requires: 2.7+, 3.3+, PyPy

2026-02-14 16:09