[Python-Dev] PEP 560: bases classes (original) (raw)

Ivan Levkivskyi levkivskyi at gmail.com
Wed Nov 15 13:39:11 EST 2017

Nick is exactly right here. Jim, if you want to propose alternative wording, then we could consider it.

-- Ivan

On 15 November 2017 at 16:37, Nick Coghlan <ncoghlan at gmail.com> wrote:

On 16 November 2017 at 00:20, Jim J. Jewett <jimjjewett at gmail.com> wrote:

I think the following will happen:

"NewList[int]" will be evaluated, and classgetitem called, so that the bases tuple will be (A, GenericAlias(NewList, int), B) # (A) I think mroentries 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 = mroentries(A, GenericAlias(NewList, int), B) # (C) I think mroentries 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 mroentries(self, origbases): ... return replacementforself My assumption as to the purpose of the extra complexity was: - given origbases, 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 | ncoghlan at gmail.com | Brisbane, Australia -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.python.org/pipermail/python-dev/attachments/20171115/a52f7c00/attachment.html>

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