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Multiple dispatch

Project description

Multiple Dispatch 2
=================

|Build Status| |Coverage Status| |Version Status| |Downloads|

This is a fork from `mroklin's multipledispatch<https://github.com/mrocklin/multipledispatch>`_, which is designed to fully support python 3's type annotation.

And it only supports python 3.3+.

Example
-------

.. code-block:: python

>>> from multipledispatch2 import dispatch

>>> @dispatch
... def add(x: int, y: int) -> int:
... return x + y

>>> @dispatch
... def add(x, y):
... return "%s + %s" % (x, y)

>>> add(1, 2)
3

>>> add(1, 'hello')
'1 + hello'

What this does
--------------

- Dispatches on all non-keyword arguments

- Supports inheritance

- Supports instance methods

- Supports union types, e.g. ``(int, float)``

- Supports builtin abstract classes, e.g. ``Iterator, Number, ...``

- Caches for fast repeated lookup

- Identifies possible ambiguities at function definition time

- Provides hints to resolve ambiguities when they occur

- Supports namespaces with optional keyword arguments

What this doesn't do
--------------------

- Vararg dispatch

.. code-block:: python

import typing

@dispatch
def add(*args: typing.Iterable[int]):
...

- Diagonal dispatch

.. code-block:: python

a = arbitrary_type()
@dispatch
def are_same_type(x: a, y: a) -> bool:
return True

- Efficient update: The addition of a new signature requires a full resolve of
the whole function. This becomes troublesome after you get to a few hundred
type signatures. It can be mitigated by halting and restarting ordering see
(``halt_ordering`` and ``restart_ordering`` functions for more information.)


Installation and Dependencies
-----------------------------

``multipledispatch2`` is on the Python Package Index (PyPI):

::

pip install multipledispatch2

or

::

easy_install multipledispatch2


``multipledispatch2`` is only supports Python 3.3+. It is pure Python and requires no dependencies beyond the standard
library.

It is, in short, a light weight dependency.


License
-------

New BSD. See License_.


Links
-----

- `Five-minute Multimethods in Python by Guido`_
- `multimethods package on PyPI`_
- `singledispatch in Python 3.4's functools`_
- `Clojure Protocols`_
- `Julia methods docs`_
- `Karpinksi notebook: *The Design Impact of Multiple Dispatch*`_
- `Wikipedia article`_
- `PEP 3124 - *Overloading, Generic Functions, Interfaces, and Adaptation*`_
- `PEP 0484 - *Type Hints*`_

.. _`Five-minute Multimethods in Python by Guido`:
http://www.artima.com/weblogs/viewpost.jsp?thread=101605
.. _`multimethods package on PyPI`:
https://pypi.python.org/pypi/multimethods
.. _`singledispatch in Python 3.4's functools`:
http://docs.python.org/3.4/library/functools.html#functools.singledispatch
.. _`Clojure Protocols`:
http://clojure.org/protocols
.. _`Julia methods docs`:
http://julia.readthedocs.org/en/latest/manual/methods/
.. _`Karpinksi notebook: *The Design Impact of Multiple Dispatch*`:
http://nbviewer.ipython.org/gist/StefanKarpinski/b8fe9dbb36c1427b9f22
.. _`Wikipedia article`:
http://en.wikipedia.org/wiki/Multiple_dispatch
.. _`PEP 3124 - *Overloading, Generic Functions, Interfaces, and Adaptation*`:
http://legacy.python.org/dev/peps/pep-3124/
.. _`PEP 0484 - *Type Hints*`:
https://www.python.org/dev/peps/pep-0484/

.. |Build Status| image:: https://travis-ci.org/mrocklin/multipledispatch.png
:target: https://travis-ci.org/mrocklin/multipledispatch
.. |Version Status| image:: https://pypip.in/v/multipledispatch/badge.png
:target: https://pypi.python.org/pypi/multipledispatch/
.. |Downloads| image:: https://pypip.in/d/multipledispatch/badge.png
:target: https://pypi.python.org/pypi/multipledispatch/
.. |Coverage Status| image:: https://coveralls.io/repos/mrocklin/multipledispatch/badge.png
:target: https://coveralls.io/r/mrocklin/multipledispatch
.. _License: https://github.com/mrocklin/multipledispatch/blob/master/LICENSE.txt

Project details


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0.4.0

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0.3.0

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0.2.0

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