patmat

patmat

Functional-style recursive pattern matching in Python. Crazy stuff.

Install

.. code-block:: sh

pip install patmat

Usage

Pattern matching with patmat:

.. code-block:: python

>>> from patmat import *
>>> Mimic({(1, Val('k')): (3, Val('v'))}).match({(1, 2): (3, 4)})
{'k': 2, 'v': 4}

Multiple dispatch generic functions:

.. code-block:: python

>>> from patmat import *
>>>
>>> @case
>>> def func(match, l=[Val('head'), ..., 3, Val('tail')]):
...     print('a list with a head {} and a tail {}'.format(match.head, match.tail))
>>>
>>> @case
>>> def func(match, l=Val('item')):
...     print('an item {}'.format(match.item))
>>>
>>> func([1, 2, 3, 4])
a list with a head 1 and a tail 4
>>> func(5)
an item: 5

More dispatch examples:

.. code-block:: python

>>> @case
>>> def func(_, x=int):
...     print('Do something with an integer.')
>>>
>>> @case
>>> def func(_, x=float):
...     print('Do something with a float.')
>>>
>>> func(1)
Do something with an integer
>>> func(1.0)
Do something with a float

Matches list, tuple, dict, types, classes with attributes. Brace yourself for the power of recursive pattern matching:

.. code-block:: python

>>> from patmat import *
>>> m = Mimic([
...     1, Type(int, Val(2)),
...     Mimic(a=3, b=[4, Val(5), 6], c=Val(7)),
...     Val(8), {Val(9): 10, Val(11): 12},
... ])
>>> class A: 
...     __init__ = lambda self, **kwargs: self.__dict__.update(kwargs)
>>> m.match([1, 2, A(a=3, b=[4, 5, 6], c=7), 8, {9: 10, 11: 12}])
{2: 2, 5: 5, 7: 7, 8: 8, 9: 9, 11: 11}