Object implementation of the OpenMath standard

pip install openmath==0.3.0



Build Status Pypi

Python OpenMath 2.0 implementation.


OpenMath is an extensible standard for representing the semantics of mathematical objects.


pip install openmath


This package provides an object implementation of OpenMath, and XML parsing/serialization.

See py-scscp for an example of use.

XML Serialization

The modules encoder and decoder provide XML de-serialization for OpenMath objects.

>>> from openmath import encoder, decoder, openmath as om
>>> xml = encoder.encode_xml(om.OMString('hello world')); xml
<Element {}OMSTR at 0x7fcb3cd82708>
>>> b = encoder.encode_bytes(om.OMString('hello world')); b
b'<OMSTR xmlns="">hello world</OMSTR>'
>>> decoder.decode_xml(xml)
OMString('hello world', id=None)
>>> decoder.decode_bytes(b, snippet=True)
OMString('hello world', id=None)

Conversions between Python and OpenMath

This package provides facilities for easy conversions from Python to OpenMath and back. The module convert contains a Converter class, which is used to implements this functionality. For convenienve, an instance of this class, DefaultConverter is provided.

The two functions to_python() and to_openmath() do the conversion as their names suggest, or raise a ValueError if no conversion is known.

By default, a Converter only implements conversions for basic Python types:

  • bools,
  • ints,
  • floats,
  • complex numbers,
  • strings,
  • bytes,
  • lists (recursively),
  • sets (recursively).

Furthermore, any object that defines an __openmath__(self) method will have that method called by to_python.

Finally, this class contains a mechanism for registering converters.

>>> from fractions import Fraction
>>> from openmath import openmath as om
>>> from openmath.convert import DefaultConverter as converter
>>> def to_om_rat(obj):
...     return om.OMApplication(om.OMSymbol('rational', cd='nums1'),
...                             list(map(converter.to_openmath, [obj.numerator, obj.denominator])))
>>> def to_py_rat(obj):
...     return Fraction(converter.to_python(obj.arguments[0]), converter.to_python(obj.arguments[1]))
>>> converter.register(Fraction, to_om_rat, 'nums1', 'rational', to_py_rat)
>>> omobj = converter.to_openmath(Fraction(5, 6)); omobj
OMApplication(OMSymbol('rational', 'nums1', id=None, cdbase=None), [OMInteger(5, id=None), OMInteger(6, id=None)], id=None, cdbase=None)
>>> converter.to_python(omobj)
Fraction(5, 6)


The source code of this project can be found on GitHub. Please use GitHub issues and pull requests to contribute to this project.


This work is supported by OpenDreamKit.


This work is licensed under the MIT License, for details see the LICENSE file.