Built-in functions, types, exceptions, and other objects.
Package to evaluate logical tag expressions by using a modified version of the Shunting Yard algorithm <https://en.wikipedia.org/wiki/Shunting-yard_algorithm>
_.
This package is a Python port of cucumbers tag expression.
It's also used by radish <https://github.com/radish-bdd/radish>
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|Build Status| |PyPI package version| |PyPI python versions|
.. code:: bash
$ pip install tag-expressions
.. code:: python
>>> from tagexpressions import parse
>>>
>>> expression = '( a and b ) or ( c and d )'
>>> compiled_expression = parse(expression)
>>> print(compiled_expression)
( ( a and b ) or ( c and d ) )
>>>
>>> data = ['a', 'b', 'c', 'd']
>>> assert compiled_expression.evaluate(data) == True
>>>
>>> data = ['a', 'c']
>>> assert compiled_expression.evaluate(data) == False
>>>
>>>
>>> expression = 'not a or b and not c or not d or e and f'
>>> compiled_expression = parse(expression)
>>> print(compiled_expression)
( ( ( not ( a ) or ( b and not ( c ) ) ) or not ( d ) ) or ( e and f ) )
>>>
>>> data = ['b', 'e', 'f']
>>> assert compiled_expression.evaluate(data) == True
>>>
>>> data = ['a', 'c', 'd']
>>> assert compiled_expression.evaluate(data) == False
Available operators
* **or** - "or" conjunction of two given variables
* **and** - "and" conjunction of two given variables
* **not** - negation of a single variable
Every other token given in an *infix* is considered a variable.
Operator precedence
From high to low:
.. |Build Status| image:: https://travis-ci.org/timofurrer/tag-expressions.png?branch=master :target: https://travis-ci.org/timofurrer/tag-expressions .. |PyPI package version| image:: https://badge.fury.io/py/tag-expressions.svg :target: https://badge.fury.io/py/tag-expressions .. |PyPI python versions| image:: https://img.shields.io/pypi/pyversions/tag-expressions.svg :target: https://pypi.python.org/pypi/tag-expressions