At 06:35 AM 8/28/2008 +0200, Michele Simionato wrote:
Multiple inheritance of metaclasses is perhaps
the strongest use case for multiple inheritance, but is it strong
enough? I mean, in real code how many times did I need that?
I would not mind make life harder for gurus and simpler for
application programmers.
Then you need to leave MI and co-operation the hell alone. Right
now, an application programmer can mix metaclasses like this:
class FooBar(Foo, Bar):
class __metaclass__(Foo.__class__, Bar.__class__): pass
...
Or, in 3.x:
class FooBarClass(Foo.__class__, Bar.__class__): pass
class FooBar(Foo, Bar, metaclass=FooBarClass):
...
Either way, this is useful in cases where Foo and Bar come from
different frameworks. That's the *only* way to get such things to
co-operate, in fact.
I do not think removing cooperation
would be so bad in practice. In many practical cases, one could just write
the metaclass by hand,
How is that making things easier for application programmers?
Maybe you would need to duplicate a couple of lines and/or to introduce
an helper function,
...which then has to have an agreed-upon protocol that all metaclass
authors have to follow... which we already have... but which you're
proposing to get rid of... so we can re-invent it lots of
times... in mutually incompatible ways. :)
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