boristhebrave / axaxaxas

A simple to use Python 3 Earley Parser

Axaxaxas

Axaxaxas - making sense of nonsense.

Axaxaxas is a Python 3.3 implementation of an Earley Parser. Earley parsers are a robust parser that can recognize any context-free grammar, with good support for amiguous grammars. They have linear performance for a wide class of grammars, and worst case O(n^3).

The main goals of this implementation are ease of use, customization, and requiring no pre-processing step for the grammar. You may find the Marpa project better suits high performance needs.

Documentation can be found at http://axaxaxas.readthedocs.org

Features

• Complete Earley Parser implemenation
• Native support for higher level constructs such as optional elements and Kleene stars
• Many options for taming ambiguity
• Completely customizable tokens, terminals and parse trees
• No pre-processing step at all - grammars can be changed on the fly

TODO

• Joop Leo's LR performance enhancements
• Better handling of infinite grammars
• Token lookahead
• Fast-first option
• Handle infinite parses better.

License

MIT License (MIT)

Copyright (c) 2015 Adam Newgas