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Table of Contents

Introduction to Bison

Bison is a general-purpose parser generator that converts an annotated context-free grammar into an LALR(1) or GLR parser for that grammar. Once you are proficient with Bison, you can use it to develop a wide range of language parsers, from those used in simple desk calculators to complex programming languages.

Bison is upward compatible with Yacc: all properly-written Yacc grammars ought to work with Bison with no change. Anyone familiar with Yacc should be able to use Bison with little trouble. You need to be fluent in C or C++ programming in order to use Bison.

The manual is available online or you can order a copy.

Downloading Bison

Released versions of GNU Bison can be found in the subdirectory /gnu/bison/ on your favorite GNU mirror. For other ways to obtain GNU Bison, please read How to get GNU Software. The latest released version will be the latest version available here at

Testing versions of alpha releases can be found on the alpha release server. A different server is used for alpha releases so that people do not confuse testing snapshots and released versions. Alpha test versions are available at The latest development sources for Bison can always be fetched through CVS. Please note that we do not suggest using Bison sources from these locations for production use.

Bison Mailing Lists

To contact Bison community for help or general discussions, use

If you have found a bug in Bison, that hasn't yet been fixed in the latest CVS sources of Bison, contact us to the e-mail address Or send a patch (made for the CVS sources, not the release sources) to the e-mail address

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