memoize decorator

"""
The memoize decorator saves arguments and then compares it
with previous arguments. If the arguments match, it returns the
result from the calculation when the arguments where
already used.

by Niklas Rosenstein
[email protected]
"""

def memoize(steps=25):
    results = {'args':[],'result':[]}
    def wrapper(f):
        def nf(*args,**kwargs):
            if (args,kwargs) in \
            results["args"]:
                return results["result"]\
                [results["args"]\
                .index((args,kwargs))]
            else:
                results["args"].append(
                (args,kwargs)         )
                r = f(*args,**kwargs)
                results["result"].append(r)
                if len(results["result"]) \
                > steps:
                    del results["args"][0]
                    del results["result"][0]
                return r
        nf.__name__ = f.__name__
        return nf
    return wrapper