Hi, I'm trying to find/write a memoizing decorator that works both for functions and methods. I've been looking at the following two samples:
http://wiki.python.org/moin/PythonDecoratorLibrary#head-11870a08b0fa59a8622201abfac735ea47ffade5 http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/325205 AFAICT, both of these seem to be targetting bare functions (the second seems to break with: unbound methods must have non-NULL im_class ). I'm using the following code to test the decorators: --- def test_memoize(memoize_fn): @memoize_fn def fn(x): print '(eval %s)' % str(x), return x print 'fn', fn(1) print 'fn', fn(1) class A(object): @memoize_fn def fn(self, x): print '(eval %s)' % str(x), return x a = A() print 'meth', a.fn(1) print 'meth', a.fn(1) --- In the method test, I get: fn() takes exactly 2 arguments (1 given) As I understand things the difficulty here is due to the way Python resolves between functions, unbound methods, and bound methods, which I have a basic sense of, and how user-defined callables fits into this picture, which I'm not very clear on. I *think* the reason this exception comes up is because user-defined callables don't automagically get a 'self' prepended to the argument list. So I've managed to get these working for both functions and methods by wrapping them in yet another function (the following is for the cookbook example, replacing 'cachedmethod'): --- def memoize(function): im = Memoize(function) def fn(*args, **kwargs): return im(*args, **kwargs) return fn --- However, this seems wasteful in that there are now 2 "wrapper" function invocations before one gets to the underlying function. I would appreciate any advice on how to proceed/clean this up. Thanks, Daishi -- http://mail.python.org/mailman/listinfo/python-list
