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PyParsing -- A Python Parsing Module ==================================== |Build Status| |Coverage| Introduction ============ The pyparsing module is an alternative approach to creating and executing simple grammars, vs. the traditional lex/yacc approach, or the use of regular expressions. The pyparsing module provides a library of classes that client code uses to construct the grammar directly in Python code. *[Since first writing this description of pyparsing in late 2003, this technique for developing parsers has become more widespread, under the name Parsing Expression Grammars - PEGs. See more information on PEGs* `here <https://en.wikipedia.org/wiki/Parsing_expression_grammar>`__ *.]* Here is a program to parse ``"Hello, World!"`` (or any greeting of the form ``"salutation, addressee!"``): .. code:: python from pyparsing import Word, alphas greet = Word(alphas) + "," + Word(alphas) + "!" hello = "Hello, World!" print(hello, "->", greet.parseString(hello)) The program outputs the following:: Hello, World! -> ['Hello', ',', 'World', '!'] The Python representation of the grammar is quite readable, owing to the self-explanatory class names, and the use of '+', '|' and '^' operator definitions. The parsed results returned from ``parseString()`` is a collection of type ``ParseResults``, which can be accessed as a nested list, a dictionary, or an object with named attributes. The pyparsing module handles some of the problems that are typically vexing when writing text parsers: - extra or missing whitespace (the above program will also handle ``"Hello,World!"``, ``"Hello , World !"``, etc.) - quoted strings - embedded comments The examples directory includes a simple SQL parser, simple CORBA IDL parser, a config file parser, a chemical formula parser, and a four- function algebraic notation parser, among many others. Documentation ============= There are many examples in the online docstrings of the classes and methods in pyparsing. You can find them compiled into `online docs <https://pyparsing-docs.readthedocs.io/en/latest/>`__. Additional documentation resources and project info are listed in the online `GitHub wiki <https://github.com/pyparsing/pyparsing/wiki>`__. An entire directory of examples can be found `here <https://github.com/pyparsing/pyparsing/tree/master/examples>`__. License ======= MIT License. See header of the `pyparsing.py <https://github.com/pyparsing/pyparsing/blob/master/pyparsing/__init__.py#L1-L23>`__ file. History ======= See `CHANGES <https://github.com/pyparsing/pyparsing/blob/master/CHANGES>`__ file. .. |Build Status| image:: https://github.com/pyparsing/pyparsing/actions/workflows/ci.yml/badge.svg :target: https://github.com/pyparsing/pyparsing/actions/workflows/ci.yml .. |Coverage| image:: https://codecov.io/gh/pyparsing/pyparsing/branch/master/graph/badge.svg :target: https://codecov.io/gh/pyparsing/pyparsing