On 16 November 2017 at 00:20, Jim J. Jewett <[email protected]> wrote:
> I *think* the following will happen:
>
> "NewList[int]" will be evaluated, and __class_getitem__ called, so
> that the bases tuple will be (A, GenericAlias(NewList, int), B)
>
> # (A) I *think* __mro_entries__ gets called with the full tuple,
> # instead of just the object it is found on.
> # (B) I *think* it is called on the results of evaluating
> # the terms within the tuple, instead of the original
> # string representation.
> _tmp = __mro_entries__(A, GenericAlias(NewList, int), B)
>
> # (C) I *think* __mro_entries__ returns a replacement for
> # just the single object, even though it was called on
> # the whole tuple, without knowing which object it
> # represents.
> bases = (A, _tmp, B)
>
My understanding of the method signature:
def __mro_entries__(self, orig_bases):
...
return replacement_for_self
My assumption as to the purpose of the extra complexity was:
- given orig_bases, a method could avoid injecting bases already listed if
it wanted to
- allowing multiple items to be returned provides a way to programmatically
combine mixins without having to define a new subclass for each combination
Cheers,
Nick.
--
Nick Coghlan | [email protected] | Brisbane, Australia
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