How to write and use curried functions

Creating curried functions is pretty straight-forward with pymonad. The tools module provides the function curry which allows you to turn any function, including python built-ins and functions which take variable numbers of arguments, into curried functions.

from pymonad.tools import curry

curry takes two parameters: The first parameter is the number of arguments to curry and the second argument is the actual function. For instance given the following function:

def add(x, y):
    return x + y

We create a curried version like this:

curried_add = curry(2, add)

# Or, if you don't need the original
#add = curry(2, add)

If a function takes a variable number of arguments you can create multiple curried versions easily.

curried_map = curry(2, map) # Takes a function and a single list
curried_map2 = curry(3, map) # Takes a function and two lists
# etc...

Whether this is a good idea or not is left as an exercise for the reader.

curry is itself a curried function so you can partially apply it and use it as a decorator to define curried functions easily:

@curry(2)
def add(x, y):
    return x + y

three = add(1, 2)
add_1 = add(1)
also_three = add_1(2)