Skip to main content

Predicates for Python.

Project description

Predicates for Python

Library for constuction predicates like (OwnedBy('alex') | OwnedBy('alice')) & HasTag('game-design') and applying them to other objects.

Motivation

I tired from reimplementation of custom predicate logic in my pet projects. So, I implemented that library.

Library focus on usability, not performance. At least, for now.

Install

pip install pydicates

Use

Minimal example

from pydicates import Predicate, common


def HasTag(tag):
    return Predicate('has_tag', tag)


def has_tag(context, tag, document):
    return tag in document['tags']


common.register('has_tag', has_tag)


document = {'tags': ('a', 'b', 'c', 'd')}


assert common(HasTag('a') & HasTag('c'), document)
assert not common(HasTag('a') & HasTag('e'), document)
assert common(HasTag('a') & ~HasTag('e'), document)
assert common(HasTag('a') & (HasTag('e') | HasTag('d')), document)

More examples can be found in ./examples directory.

See ./examples/documents_check.py for API description.

See ./tests for more examples.

Limitations

  • Can not chain redefined comparisons: a < b < c is equal to (a < b) and (b < c) which translates by Python to b < c, because a < b is object (Predicate) and always True.

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

pydicates-0.1.1.tar.gz (5.2 kB view hashes)

Uploaded source

Built Distribution

pydicates-0.1.1-py3-none-any.whl (6.1 kB view hashes)

Uploaded py3

Supported by

AWS AWS Cloud computing Datadog Datadog Monitoring Facebook / Instagram Facebook / Instagram PSF Sponsor Fastly Fastly CDN Google Google Object Storage and Download Analytics Huawei Huawei PSF Sponsor Microsoft Microsoft PSF Sponsor NVIDIA NVIDIA PSF Sponsor Pingdom Pingdom Monitoring Salesforce Salesforce PSF Sponsor Sentry Sentry Error logging StatusPage StatusPage Status page