Metadata-Version: 2.1
Name: attrs
Version: 21.2.0
Summary: Classes Without Boilerplate
Home-page: https://www.attrs.org/
Author: Hynek Schlawack
Author-email: hs@ox.cx
Maintainer: Hynek Schlawack
Maintainer-email: hs@ox.cx
License: MIT
Project-URL: Documentation, https://www.attrs.org/
Project-URL: Changelog, https://www.attrs.org/en/stable/changelog.html
Project-URL: Bug Tracker, https://github.com/python-attrs/attrs/issues
Project-URL: Source Code, https://github.com/python-attrs/attrs
Project-URL: Funding, https://github.com/sponsors/hynek
Project-URL: Tidelift, https://tidelift.com/subscription/pkg/pypi-attrs?utm_source=pypi-attrs&utm_medium=pypi
Project-URL: Ko-fi, https://ko-fi.com/the_hynek
Keywords: class,attribute,boilerplate
Platform: UNKNOWN
Classifier: Development Status :: 5 - Production/Stable
Classifier: Intended Audience :: Developers
Classifier: Natural Language :: English
Classifier: License :: OSI Approved :: MIT License
Classifier: Operating System :: OS Independent
Classifier: Programming Language :: Python
Classifier: Programming Language :: Python :: 2
Classifier: Programming Language :: Python :: 2.7
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.5
Classifier: Programming Language :: Python :: 3.6
Classifier: Programming Language :: Python :: 3.7
Classifier: Programming Language :: Python :: 3.8
Classifier: Programming Language :: Python :: 3.9
Classifier: Programming Language :: Python :: 3.10
Classifier: Programming Language :: Python :: Implementation :: CPython
Classifier: Programming Language :: Python :: Implementation :: PyPy
Classifier: Topic :: Software Development :: Libraries :: Python Modules
Requires-Python: >=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*
Description-Content-Type: text/x-rst
Provides-Extra: docs
Provides-Extra: tests_no_zope
Provides-Extra: tests
Provides-Extra: dev
License-File: LICENSE
License-File: AUTHORS.rst

======================================
``attrs``: Classes Without Boilerplate
======================================


``attrs`` is the Python package that will bring back the **joy** of **writing classes** by relieving you from the drudgery of implementing object protocols (aka `dunder <https://nedbatchelder.com/blog/200605/dunder.html>`_ methods).
`Trusted by NASA <https://docs.github.com/en/github/setting-up-and-managing-your-github-profile/personalizing-your-profile#list-of-qualifying-repositories-for-mars-2020-helicopter-contributor-badge>`_ for Mars missions since 2020!

Its main goal is to help you to write **concise** and **correct** software without slowing down your code.

.. teaser-end

For that, it gives you a class decorator and a way to declaratively define the attributes on that class:

.. -code-begin-

.. code-block:: pycon

   >>> import attr

   >>> @attr.s
   ... class SomeClass(object):
   ...     a_number = attr.ib(default=42)
   ...     list_of_numbers = attr.ib(factory=list)
   ...
   ...     def hard_math(self, another_number):
   ...         return self.a_number + sum(self.list_of_numbers) * another_number


   >>> sc = SomeClass(1, [1, 2, 3])
   >>> sc
   SomeClass(a_number=1, list_of_numbers=[1, 2, 3])

   >>> sc.hard_math(3)
   19
   >>> sc == SomeClass(1, [1, 2, 3])
   True
   >>> sc != SomeClass(2, [3, 2, 1])
   True

   >>> attr.asdict(sc)
   {'a_number': 1, 'list_of_numbers': [1, 2, 3]}

   >>> SomeClass()
   SomeClass(a_number=42, list_of_numbers=[])

   >>> C = attr.make_class("C", ["a", "b"])
   >>> C("foo", "bar")
   C(a='foo', b='bar')


After *declaring* your attributes ``attrs`` gives you:

- a concise and explicit overview of the class's attributes,
- a nice human-readable ``__repr__``,
- a complete set of comparison methods (equality and ordering),
- an initializer,
- and much more,

*without* writing dull boilerplate code again and again and *without* runtime performance penalties.

On Python 3.6 and later, you can often even drop the calls to ``attr.ib()`` by using `type annotations <https://www.attrs.org/en/latest/types.html>`_.

This gives you the power to use actual classes with actual types in your code instead of confusing ``tuple``\ s or `confusingly behaving <https://www.attrs.org/en/stable/why.html#namedtuples>`_ ``namedtuple``\ s.
Which in turn encourages you to write *small classes* that do `one thing well <https://www.destroyallsoftware.com/talks/boundaries>`_.
Never again violate the `single responsibility principle <https://en.wikipedia.org/wiki/Single_responsibility_principle>`_ just because implementing ``__init__`` et al is a painful drag.


.. -getting-help-

Getting Help
============

Please use the ``python-attrs`` tag on `StackOverflow <https://stackoverflow.com/questions/tagged/python-attrs>`_ to get help.

Answering questions of your fellow developers is also a great way to help the project!


.. -project-information-

Project Information
===================

``attrs`` is released under the `MIT <https://choosealicense.com/licenses/mit/>`_ license,
its documentation lives at `Read the Docs <https://www.attrs.org/>`_,
the code on `GitHub <https://github.com/python-attrs/attrs>`_,
and the latest release on `PyPI <https://pypi.org/project/attrs/>`_.
It’s rigorously tested on Python 2.7, 3.5+, and PyPy.

We collect information on **third-party extensions** in our `wiki <https://github.com/python-attrs/attrs/wiki/Extensions-to-attrs>`_.
Feel free to browse and add your own!

If you'd like to contribute to ``attrs`` you're most welcome and we've written `a little guide <https://www.attrs.org/en/latest/contributing.html>`_ to get you started!


``attrs`` for Enterprise
------------------------

Available as part of the Tidelift Subscription.

The maintainers of ``attrs`` and thousands of other packages are working with Tidelift to deliver commercial support and maintenance for the open source packages you use to build your applications.
Save time, reduce risk, and improve code health, while paying the maintainers of the exact packages you use.
`Learn more. <https://tidelift.com/subscription/pkg/pypi-attrs?utm_source=pypi-attrs&utm_medium=referral&utm_campaign=enterprise&utm_term=repo>`_


Release Information
===================

21.2.0 (2021-05-07)
-------------------

Backward-incompatible Changes
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

- We had to revert the recursive feature for ``attr.evolve()`` because it broke some use-cases -- sorry!
  `#806 <https://github.com/python-attrs/attrs/issues/806>`_
- Python 3.4 is now blocked using packaging metadata because ``attrs`` can't be imported on it anymore.
  To ensure that 3.4 users can keep installing  ``attrs`` easily, we will `yank <https://pypi.org/help/#yanked>`_ 21.1.0 from PyPI.
  This has **no** consequences if you pin ``attrs`` to 21.1.0.
  `#807 <https://github.com/python-attrs/attrs/issues/807>`_

`Full changelog <https://www.attrs.org/en/stable/changelog.html>`_.

Credits
=======

``attrs`` is written and maintained by `Hynek Schlawack <https://hynek.me/>`_.

The development is kindly supported by `Variomedia AG <https://www.variomedia.de/>`_.

A full list of contributors can be found in `GitHub's overview <https://github.com/python-attrs/attrs/graphs/contributors>`_.

It’s the spiritual successor of `characteristic <https://characteristic.readthedocs.io/>`_ and aspires to fix some of it clunkiness and unfortunate decisions.
Both were inspired by Twisted’s `FancyEqMixin <https://twistedmatrix.com/documents/current/api/twisted.python.util.FancyEqMixin.html>`_ but both are implemented using class decorators because `subclassing is bad for you <https://www.youtube.com/watch?v=3MNVP9-hglc>`_, m’kay?