Riccardo Galli wrote (approximately):
> I need a class to behave as a factory method for its children so that I could
> inherit
> from it and still use it as a factory.
Several others suggest you probably don't want to do this; I concur.
Separating the factory from the interface (I presume you are doing some
isinstance checking) is probably a good idea. If, for some reason, you
feel you must implement your original plan, the following code should
outline the trick (look up __new__ and study the code).
class Interf(object):
def __new__(klass, kind, *args, **kwargs):
if kind is None:
return object.__new__(klass, *args, **kwargs)
elif kind == 'a':
return Sub1(*args, **kwargs)
else:
assert kind == 'b'
return Sub2(*args, **kwargs)
def __repr__(self):
return '%s(%s)' % (self.__class__.__name__, ', '.join(
'%s=%r' % pair
for pair in sorted(vars(self).items())))
class Sub1(Interf):
def __new__(klass, *args, **kwargs):
return Interf.__new__(klass, None, *args, **kwargs)
def __init__(self, *args, **kwargs):
self.args = args
self.kwargs = kwargs
class Sub2(Interf):
def __new__(klass, *args, **kwargs):
return Interf.__new__(klass, None, *args, **kwargs)
def __init__(self, *args, **kwargs):
self.xargs = args
self.xkwargs = kwargs
--Scott David Daniels
[EMAIL PROTECTED]
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