The Omega parsing framework
- Author: Timothy Allen <firstname.lastname@example.org>
- Website: https://gitlab.com/Screwtapello/python-omega
- Mailing-list: <email@example.com>
- Licence: The Omega package and all associated documentation and example code are placed under the GNU GPLv3. See the included file LICENCE for details.
Omega is a framework designed to help you build parsers for text and binary data. It creates a recursive-descent/Parsing-Expression-Grammar parser given a description of the file-format in the concise Omega language, but if your file-format can’t be described in pure Omega, it’s easy to extend with Python.
For example, here’s a very simple parser for arithmetic expressions:
>>> import omega >>> class ArithmeticParser(omega.BaseParser): ... __grammar = """ ... digit = '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' ... | '8' | '9' ; ... term = digit+:ds -> (int("".join(ds))) ... | '(' sum:s ')' -> (s) ... ; ... product = term:a '*' product:b -> (a * b) ... | term:a '/' product:b -> (a / b) ... | term ... ; ... sum = product:a '+' sum:b -> (a + b) ... | product:a '-' sum:b -> (a - b) ... | product ... ; ... """
And here it is in action:
>>> ArithmeticParser.match("1") 1 >>> ArithmeticParser.match("1+1") 2 >>> ArithmeticParser.match("6*9") 54 >>> ArithmeticParser.match("2+3*4") 14 >>> ArithmeticParser.match("(2+3)*4") 20
Omega is a pure-Python package, and requires only Python 3.4 or higher to be installed.
What’s In The Box
- README.md is this file.
- TODO.md is a list of possible future additions to the package.
- LICENCE is the full text of the licence this software is released under, the GPLv3.
- setup.py is the standard Python packaging script.
- docs is a subdirectory containing all the documentation for Omega, including language and library references, a Python API reference, and a tutorial.
- examples is a subdirectory containing various self-contained example parsers written in Omega.
- omega is the Python package itself.
Omega uses the standard distutils packaging system for Python, so if you have a source tarball, you should be able to install it with:
python setup.py install
…and of course all the other standard distutils commands are available.
The complete documentation is packaged with Omega source releases, and is also available online at https://gitlab.com/Screwtapello/python-omega/wikis/home