Build a Parser with Python
onlamp.com: Building Recursive Descent Parsers with Python
Several pyparsing features help developers create their text-parsing functions quickly:
* Grammars are native Python, so no separate grammar definition files are required
* No special syntax is required, outside + for And, ^ for Or (longest, or “greedy” match), | for MatchFirst (first match), and ~ for Not
* No separate code-generation step is required
* It implicitly skips white space and comments that may appear between parse elements; there is no need to clutter your grammar with markers for ignorable text