Generic Dispatch for Python

This is a very basic generic dispatch system for Python. This is inspired by Haskell's syntax for writing conditional function definitions, hence the package name.

Quick intro

You can see examples in the tests directory, but here is a very simple example.

In Haskell you might implement a reverse function the following way:

reverse' :: [a] -> [a]  
reverse' [] = []  
reverse' (x:xs) = reverse' xs ++ [x] 

This method uses the type system to define the function for the empty list and for basically the other case.

Here's the cooresponding solution using this dispatch system:

from typedispatch import *

@dispatch([])
def reverse(l):
    return []

@dispatch(iterable)
def reverse(l):
    return reverse(l[1:]) + l[:1]

So yeah, this is pretty cool syntactic sugar. What happens if we run reverse(5), which is clearly not defined given the above definition?

>>> reverse(5)
Traceback (most recent call last):
    ...
    NameError: named function 'reverse' with arguments is not defined

So we get what we'd expect: the function is not "defined" for this specific argument.