[Python-Dev] type categories

[Aahz]

On Fri, Sep 13, 2002, Guido van Rossum wrote:
>Aahz:
>> 
>> I'm curious, and I don't recall having seen anything about this: why
>> wouldn't we simply use attributes to hold this information, like
>> __slots__?  After all, attributes get inherited, too, and there's no
>> need to pretzel the syntax.  Using attributes IMO would make it easier
>> to handle the case where derived classes need to mangle type and
>> interface declarations.
> 
> That's exactly what Zope does with the __inherits__ attribute.
> 
> But it's got limitations: there's only one __inherits__ attribute, so
> it isn't automatically merged properly on multiple inheritance, and
> adding one new interface to it means you have to copy or reference the
> base class __inherits__ attribute.

Isn't that what metaclasses are for?
-- 
Aahz (aahz@pythoncraft.com)           <*>         http://www.pythoncraft.com/

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