Decorators for multimethods

[Roman Suzi]

hi!

I've found one more nice use case for decorators. I feel multimethods
could be made even nicier by defining multimethods inside special
class. But I have not figured out how to do it yet.

#!/bin/env python2.4
if "We have Neel Krishnaswami module Multimethod.py":

import Multimethod

class Foo: pass

class Bar(Foo): pass

def multimethod(g, *args):
def make_multimethod(func):
mm = Multimethod.Method(tuple(args), func)
g.add_method(mm)
return mm
return make_multimethod

g = Multimethod.Generic()

@multimethod(g, Foo, Foo)
def m1(a, b): return 'foofoo'

@multimethod(g, Foo, Bar)
def m2(a, b): return 'foobar'

@multimethod(g, Bar, Foo)
def m3(a, b): return 'barfoo'

try:
print 'Argtypes ', 'Result'
print 'Foo, Foo:', g(Foo(), Foo())
print 'Foo, Bar:', g(Foo(), Bar())
print 'Bar, Foo:', g(Bar(), Foo())
print 'Bar, Bar:', g(Bar(), Bar())
except Multimethod.AmbiguousMethodError:
print 'Failed due to AmbiguousMethodError'


Sincerely yours, Roman Suzi