[EMAIL PROTECTED] wrote:
> Hey, I have the following code that has to send every command it
> receives to a list of backends.
<snip>
> I would like to write each method like:
>
> flush = multimethod()
Here's one way, using a metaclass:
class multimethod(object):
def transform(self, attr):
def dispatch(self, *args, **kw):
results = []
for b in self.backends:
results.append(getattr(b, attr)(*args, **kw))
return results
return dispatch
def multimethodmeta(name, bases, dict):
"""Transform each multimethod object into an actual method"""
for attr in dict:
if isinstance(dict[attr], multimethod):
dict[attr] = dict[attr].transform(attr)
return type(name, bases, dict)
class MultiBackend(object):
__metaclass__ = multimethodmeta
def __init__(self, backends):
self.backends = backends
add = multimethod()
class Foo(object):
def add(self, x, y):
print 'in Foo.add'
return x + y
class Bar(object):
def add(self, x, y):
print 'in Bar.add'
return str(x) + str(y)
m = MultiBackend([Foo(), Bar()])
print m.add(3, 4)
# Output:
in Foo.add
in Bar.add
[7, '34']
--Ben
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