Dep-Logic

Python dependency specifications supporting logical operations

Installation

pip install dep-logic

This library requires Python 3.8 or later.

Currently, it contains two sub-modules:

• dep_logic.specifier - a module for parsing and calculating PEP 440 version specifiers.
• dep_logic.markers - a module for parsing and calculating PEP 508 environment markers.

What does it do?

This library allows logic operations on version specifiers and environment markers.

For example:

>>> from dep_logic.specifiers import parse_version_specifier
>>>
>>> a = parse_version_specifier(">=1.0.0")
>>> b = parse_version_specifier("<2.0.0")
>>> print(a & b)
>=1.0.0,<2.0.0
>>> a = parse_version_specifier(">=1.0.0,<2.0.0")
>>> b = parse_version_specifier(">1.5")
>>> print(a | b)
>=1.0.0

For markers:

>>> from dep_logic.markers import parse_marker
>>> m1 = parse_marker("python_version < '3.8'")
>>> m2 = parse_marker("python_version >= '3.6'")
>>> print(m1 & m2)
python_version < "3.8" and python_version >= "3.6"

About the project

This project is based on @sdispater's poetry-core code, but it includes additional packages and a lark parser, which increases the package size and makes it less reusable.

Furthermore, poetry-core does not always comply with PEP-508. As a result, this project aims to offer a lightweight utility for dependency specification logic using PyPA's packaging.

Caveats

Logic operations with ===<string> specifiers is partially supported.