Metadata-Version: 2.1
Name: attrs
Version: 19.1.0
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: Bug Tracker, https://github.com/python-attrs/attrs/issues
Project-URL: Source Code, https://github.com/python-attrs/attrs
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 :: 3.4
Classifier: Programming Language :: Python :: 3.5
Classifier: Programming Language :: Python :: 3.6
Classifier: Programming Language :: Python :: 3.7
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.*
Provides-Extra: dev
Requires-Dist: coverage ; extra == 'dev'
Requires-Dist: hypothesis ; extra == 'dev'
Requires-Dist: pympler ; extra == 'dev'
Requires-Dist: pytest ; extra == 'dev'
Requires-Dist: six ; extra == 'dev'
Requires-Dist: zope.interface ; extra == 'dev'
Requires-Dist: sphinx ; extra == 'dev'
Requires-Dist: pre-commit ; extra == 'dev'
Provides-Extra: docs
Requires-Dist: sphinx ; extra == 'docs'
Requires-Dist: zope.interface ; extra == 'docs'
Provides-Extra: tests
Requires-Dist: coverage ; extra == 'tests'
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Requires-Dist: pympler ; extra == 'tests'
Requires-Dist: pytest ; extra == 'tests'
Requires-Dist: six ; extra == 'tests'
Requires-Dist: zope.interface ; extra == 'tests'
.. image:: https://www.attrs.org/en/latest/_static/attrs_logo.png
:alt: attrs Logo
======================================
``attrs``: Classes Without Boilerplate
======================================
.. image:: https://readthedocs.org/projects/attrs/badge/?version=stable
:target: https://www.attrs.org/en/stable/?badge=stable
:alt: Documentation Status
.. image:: https://travis-ci.org/python-attrs/attrs.svg?branch=master
:target: https://travis-ci.org/python-attrs/attrs
:alt: CI Status
.. image:: https://codecov.io/github/python-attrs/attrs/branch/master/graph/badge.svg
:target: https://codecov.io/github/python-attrs/attrs
:alt: Test Coverage
.. image:: https://img.shields.io/badge/code%20style-black-000000.svg
:target: https://github.com/ambv/black
:alt: Code style: black
.. teaser-begin
``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).
Its main goal is to help you to write **concise** and **correct** software without slowing down your code.
.. -spiel-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,
- 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.
.. -testimonials-
Testimonials
============
**Amber Hawkie Brown**, Twisted Release Manager and Computer Owl:
Writing a fully-functional class using attrs takes me less time than writing this testimonial.
**Glyph Lefkowitz**, creator of `Twisted <https://twistedmatrix.com/>`_, `Automat <https://pypi.org/project/Automat/>`_, and other open source software, in `The One Python Library Everyone Needs <https://glyph.twistedmatrix.com/2016/08/attrs.html>`_:
I’m looking forward to is being able to program in Python-with-attrs everywhere.
It exerts a subtle, but positive, design influence in all the codebases I’ve see it used in.
**Kenneth Reitz**, author of `Requests <http://www.python-requests.org/>`_ and Developer Advocate at DigitalOcean, (`on paper no less <https://twitter.com/hynek/status/866817877650751488>`_!):
attrs—classes for humans. I like it.
**Łukasz Langa**, prolific CPython core developer and Production Engineer at Facebook:
I'm increasingly digging your attr.ocity. Good job!
.. -end-
.. -project-information-
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 great way to help the project!
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, 3.4+, 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!
Release Information
===================
19.1.0 (2019-03-03)
-------------------
Backward-incompatible Changes
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
- Fixed a bug where deserialized objects with ``cache_hash=True`` could have incorrect hash code values.
This change breaks classes with ``cache_hash=True`` when a custom ``__setstate__`` is present.
An exception will be thrown when applying the ``attrs`` annotation to such a class.
This limitation is tracked in issue `#494 <https://github.com/python-attrs/attrs/issues/494>`_.
`#482 <https://github.com/python-attrs/attrs/issues/482>`_
Changes
^^^^^^^
- Add ``is_callable``, ``deep_iterable``, and ``deep_mapping`` validators.
* ``is_callable``: validates that a value is callable
* ``deep_iterable``: Allows recursion down into an iterable,
applying another validator to every member in the iterable
as well as applying an optional validator to the iterable itself.
* ``deep_mapping``: Allows recursion down into the items in a mapping object,
applying a key validator and a value validator to the key and value in every item.
Also applies an optional validator to the mapping object itself.
You can find them in the ``attr.validators`` package.
`#425 <https://github.com/python-attrs/attrs/issues/425>`_
- Fixed stub files to prevent errors raised by mypy's ``disallow_any_generics = True`` option.
`#443 <https://github.com/python-attrs/attrs/issues/443>`_
- Attributes with ``init=False`` now can follow after ``kw_only=True`` attributes.
`#450 <https://github.com/python-attrs/attrs/issues/450>`_
- ``attrs`` now has first class support for defining exception classes.
If you define a class using ``@attr.s(auto_exc=True)`` and subclass an exception, the class will behave like a well-behaved exception class including an appropriate ``__str__`` method, and all attributes additionally available in an ``args`` attribute.
`#500 <https://github.com/python-attrs/attrs/issues/500>`_
- Clarified documentation for hashing to warn that hashable objects should be deeply immutable (in their usage, even if this is not enforced).
`#503 <https://github.com/python-attrs/attrs/issues/503>`_
`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?