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[Python-Dev] PEP 487: Simpler customization of class creation

Eric Fahlgren ericfahlgren at gmail.com
Wed Jun 22 13:05:50 EDT 2016 
On Wed 2016-06-22 Eric Snow [mailto:ericsnowcurrently at gmail.com] wrote:
> The problem I have with this is that it still doesn't give any strong relationship with the class definition.
> Certainly in most cases it will amount to the same thing.  However, there is no way to know if cls.__dict__ 
> represents the class definition or not.  You also lose knowing whether or not a class came from a definition
> (or acts as though it did).  Finally, __definition_order__ makes the relationship with the definition order clear,
>  whereas cls.__dict__ does not.
> Instead of being an obvious tool, with cls.__dict__ that relationship would be tucked away where only a
>  few folks with deep knowledge of Python would be in a position to take advantage.

I see this as being grossly/loosely analogous to traversing __bases__ vs calling mro(), so I feel the
same rationale applies to adding __definition_order__ as mro.

Eric
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