memoization.py

#!/usr/bin/env python


def memoize(f):
    def wrapped(self):
        attr_name = '_memoized_%s' % f.func_name
        if not hasattr(self, attr_name):
            setattr(self, attr_name, f(self))
        return getattr(self, attr_name)
    return wrapped


class Example(object):

    @property
    @memoize
    def foo(self):
        print "calculating foo"
        return 12

    @property
    @memoize
    def bar(self):
        print "calculating bar"
        return 42

if __name__ == '__main__':
    e = Example()
    print e.foo
    print e.bar
    print e.foo
    print e.bar