Skip to main content

Built-in functions, types, exceptions, and other objects.

Project description

Package to evaluate logical tag expressions by using a modified version of the Shunting Yard algorithm. This package is a Python port of cucumbers tag expression.

It’s also used by radish.

Build Status PyPI package version PyPI python versions

Installing

$ pip install tag-expressions

Here is a tease

>>> 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

Usage

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:

  • ()

  • or

  • and

  • not

Project details


Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

tag-expressions-1.1.1.tar.gz (5.6 kB view hashes)

Uploaded Source

Built Distribution

tag_expressions-1.1.1-py3-none-any.whl (5.1 kB view hashes)

Uploaded Python 3

Supported by

AWS AWS Cloud computing and Security Sponsor Datadog Datadog Monitoring Fastly Fastly CDN Google Google Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Sentry Sentry Error logging StatusPage StatusPage Status page