Python PLY

PLY is an implementation of lex and yacc parsing tools for Python.

Main Features:

- It's implemented entirely in Python.

- It uses LR-parsing which is reasonably efficient and well suited for larger grammars.
- PLY provides most of the standard lex/yacc features including support for empty productions, precedence rules, error recovery, and support for ambiguous grammars.
- PLY is straightforward to use and provides very extensive error checking.