Patterns 
Pattern matching for python. Works in Python 2.7, 3.3+ and pypy.
Installation
pip install patterns
Usage
from patterns import patterns, Mismatch
@patterns
def factorial():
if 0: 1
if n is int: n * factorial(n-1)
if []: []
if [x] + xs: [factorial(x)] + factorial(xs)
if {'n': n, 'f': f}: f(factorial(n))
assert factorial(0) == 1
assert factorial(5) == 120
assert factorial([3,4,2]) == [6, 24, 2]
assert factorial({'n': [5, 1], 'f': sum}) == 121
factorial('hello') # raises MismatchSee tests for more examples.
TODO
- docs
- aliases for structures
- destructure objects
- name parameter
- better handling of
Mismatchpassing to function env - non-strict dict matching