The Marpa parser

This is Jeffrey Kegler's website for Marpa, a parsing algorithm


The official Marpa starting page.


The Ocean of Awareness blog: home page, chronological index, and annotated index.

Marpa::R2 (active distribution): CPAN | MetaCPAN

Mailing List

Github repository

Jeffrey Kegler's personal website

Marpa is a parsing algorithm. It is new, but very much based on earlier work by Jay Earley, Joop Leo, John Aycock and R. Nigel Horspool. Marpa is intended to replace, and to go well beyond, recursive descent and the yacc family of parsers.

Learning about Marpa

What you are looking at is the web site maintained by the author of Marpa (Jeffrey Kegler). It is NOT the best page for starting to learn about Marpa. Good places to do that are:

Other Marpa resources

Discussion of Marpa currently centers around the "marpa parser" Google Group and the IRC channel: #marpa on

Most of the posts on Ocean of Awareness, my blog, are about Marpa. To get oriented in my blog, start at its annotated list of the most interesting Marpa posts.

If you are interested in tutorials,


For those interested in the mathematics behind Marpa, there's a paper with pseudocode, and proofs of correctness and of my complexity claims.

Marpa internals

Libmarpa is a C library, and is the core of Marpa.

Marpa internals: These are resources of interest only to those working on the internals of Marpa itself -- "bleeding edge" documentation, etc.