[Python-Dev] PEP 549: Instance Properties (aka: module properties)

Cody Piersall cody.piersall at gmail.com
Wed Sep 6 13:13:52 EDT 2017

On Wed, Sep 6, 2017 at 10:26 AM, Guido van Rossum <guido at python.org> wrote:
> So we've seen a real use case for __class__ assignment: deprecating things on access. That use case could also be solved if modules natively supported defining __getattr__ (with the same "only used if attribute not found otherwise" semantics as it has on classes), but it couldn't be solved using @property (or at least it would be quite hacky).
> Is there a real use case for @property? Otherwise, if we're going to mess with module's getattro, it makes more sense to add __getattr__, which would have made Nathaniel's use case somewhat simpler. (Except for the __dir__ thing -- what else might we need?)
> --
> --Guido van Rossum (python.org/~guido)

I think a more natural way for the __dir__ problem would be to update
module_dir() in moduleobject.c to check if __all__ is defined and then
just return that list if it is defined.  I think that would be a
friendlier default for __dir__ anyway.


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