Programming Forums - pyparsing - Python parser library

Pyparsing is a Python module for creating parsers. Here is a parser for "Hello, World!", or any string of the form "<greeting>, <person>!":

greeting = Word(alphas) + "," + Word(alphas) + "!"

print greeting.parseString("Hello, World!")

print greeting.parseString("Yo, Adrian!")

prints:

['Hello', ',', 'World', '!']

['Yo', ',', 'Adrian', '!']

Pyparsing can be used to parse text, scan text, and transform text. The Wiki (and the source and docs distributions) contain a number of examples, and epydoc class documentation. UML class diagrams are also included. I gave two presentations on pyparsing at PyCon'06, and there are links to online versions at the Wiki documentation page. Google for "pyparsing" to find more online material.

Here is a short list of some of the examples provided:
- "Hello, World!" (English, Korean, Greek, and Spanish)
- chemical formulas
- configuration file parser
- web page URL extractor
- 5-function arithmetic expression parser
- subset of CORBA IDL
- chess portable game notation
- simple SQL parser
- search query parser
- EBNF parser/compiler
- Python value string parser (lists, dicts, tuples, with nesting) (safe alternative to eval)
- HTML tag stripper
- S-expression parser
- macro substitution preprocessor

You can find what other uses pyparsing has been put to at the Wiki Who's Using Pyparsing page.

I just posted the latest version update to SourceForge, and you can find out more at the pyparsing Wiki: http://pyparsing.wikispaces.com.