NLTK Home (Natural Language Toolkit) - and if you want something more powerful and flexible, this is so to speak the grab bag for parsers. Focus is on the analysis of natural languages, hence also things like stemmers (stem finding for word forms) are included. Could be overkill for simple embedded languages, though.
Archive 12. March 2010
Python Package Index : Esrapy 0.5 - a parser and lexer toolkit completely in Python. Might become interesting in some projects later, at least for smaller configuration languages.