Entry

Currying

Jul 5th, 2000 09:59
Nathan Wallace, Hans Nowak, Snippet 23, Michael Christopher Vanier

"""
Packages: functional_programming
"""

"""
Here's a couple of nifty tools I came up with today.  I'm sure it's been
done before, but what the heck :-)  It made me wonder, though: are there
any functions that could be implemented in a functional programming
language that are impossible to do in python?

Mike
"""

#
# Currying functions.
#

class curry:
    def __init__(self, func, arg):
        self.func = func
        self.arg = tuple([arg])

    def __call__(self, *args, **kw):
        return apply(self.func, self.arg + args, kw)

#
# Transforming binary operators into functions.
# N.B. There's no error checking -- user beware!
#

def op(opstr):
    result = "lambda x, y: x %s y" % opstr
    func = eval(result)
    return func


if __name__ == '__main__':
    s = [1, 2, 3, 4, 5]
    n = 10
    multn = curry(op('*'), n)
    print s, "\n", map(multn, s)