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.. image:: https://img.shields.io/pypi/pyversions/quacks.svg :target: https://pypi.python.org/pypi/quacks

.. image:: https://github.com/ariebovenberg/quacks/actions/workflows/build.yml/badge.svg :target: https://github.com/ariebovenberg/quacks/actions/workflows/build.yml

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.. image:: https://img.shields.io/badge/code%20style-black-000000.svg :target: https://github.com/psf/black

.. epigraph::

If it walks like a duck and it quacks like a duck, then it must be a duck

Thanks to PEP544 <https://www.python.org/dev/peps/pep-0544/>_, Python now has protocols: a way to define duck typing statically. This library gives you some niceties to make common idioms easier.

.. code-block:: bash

pip install quacks

⚠️ For type checking to work with mypy, you'll need to enable the plugin in your mypy config file <https://mypy.readthedocs.io/en/latest/config_file.html>_:

.. code-block:: ini

[mypy] plugins = quacks

Easy read-only protocols ^^^^^^^^^^^^^^^^^^^^^^^^

Defining read-only protocols is great for encouraging immutability and working with frozen dataclasses. Use the readonly decorator:

.. code-block:: python

from quacks import readonly

@readonly
class User(Protocol):
    id: int
    name: str
    is_premium: bool

Without this decorator, we'd have to write quite a lot of cruft, reducing readability:

.. code-block:: python

class User(Protocol):
    @property
    def id(self) -> int: ...
    @property
    def name(self) -> str: ...
    @property
    def is_premium(self) -> bool: ...