The parsing module is an alternative approach to creating and executing simple grammars, vs. the traditional lex/yacc approach, or the use of regular expressions. the parsing module provides a library of classes that client code uses to construct the grammar directly in python code.

here's an example:

from pyparsing import word, alphas
greet = word(alphas) + "," + word(alphas) + "!"
hello = "hello, world!"
print hello, "->", greet.parsestring(hello)
this package contains documentation for python-pyparsing.