PyGgy

Version 0.4.1
2004-10-20

What is PyGgy

PyGgy is a python package for generating parsers and lexers in python. The PyGgy distribution contains two tools:

PyLly - (Pronounced "pile-ey") A lexer generator that generates DFA tables for lexing tokens.
PyGgy - (Pronounced "piggy") A parser generator that generates SLR tables for a GLR parsing engine.

The PyLly program is used to pregenerate tables for a finite state machine from a lexer specification. There is a lexer engine that uses the tables to tokenize an input stream.

The PyGgy program is used to pregenerate parser tables from a parser specification. There is a GLR parsing engine that uses the tables to parse a stream of input tokens. Because GLR parsing is used, the parser can deal with arbitrary grammars, even if they are recursive or ambiguous.

PyGgy is self hosting -- PyGgy parsers and PyLly lexers are used to process the specification files used by both PyGgy and PyLly.

The current version of PyGgy is 0.4.1. The 0.4 release contains minor bug fixes over the 0.3 release. The 0.4.1 build is a re-roll of the 0.4 version that fixed a minor packaging issue. This is an alpha release; the public interfaces are subject to change, and there may be bugs in the code. This version of PyGgy is placed in the public domain. This means anyone can do anything with it with no restrictions whatsoever.

Download

This is where you can download PyGgy version 0.4.1. Older versions are also here:

Documentation

The documentation for pyggy-0.4 can be found at http://www.lava.net/~newsham/pyggy/html.

Install

To install the PyGgy package, unpack the archive, change into the "pyggy" directory and run the setup program:

    $ ./setup.py install

Frequently Asked Questions

Is PyGgy a Bison replacement?
PyGgy provides similar functionality to Bison, but is written in Python for Python based parsers. Bison is also a lot more mature. While Bison did not originally support GLR parsing, recent versions have this capability. In addition to these differences, PyGgy also contains a lexer generator similar to Flex's.

Home Page and Author

PyGgy's home page is currently http://www.lava.net/~newsham/pyggy/. If this address changes in the future, this web page should point to the new home page.

The author of this release is Tim Newsham.

Mailing List

Join the PyGgy mailing list or view the archives by visiting http://groups-beta.google.com/group/pyggy.