On Sat, Feb 22, 2020 at 4:45 PM Brandt Bucher <brandtbuc...@gmail.com> wrote:
> [quoting Nick] > > collections.Mapping and collections.MutableMapping could provide > concrete method implementations that make subclasses behave in a way that's > similar to built-in dicts > > Hm, haven't thought too much about this (I don't have much experience with > the ABCs). Would they return dicts, or call the self.copy and self.update > methods? > > Those are just hypothetical questions for now; I don't necessarily want to > dig too far into that discussion again. But I agree that it's definitely > worth considering. ;) > Mapping and MutableMapping don't have copy() methods -- these are intentionally narrower interfaces than dict. I think we should leave them alone. The PEP does *not* propose to add `|` to Mapping, and that's intentional. Because of this I think we should also not add `|=` to MutableMapping, even though it does have an update() method. Adding it (even with a default implementation) could cause discrepancies to virtual subclasses registered with MutableMapping.register(C). -- --Guido van Rossum (python.org/~guido) *Pronouns: he/him **(why is my pronoun here?)* <http://feministing.com/2015/02/03/how-using-they-as-a-singular-pronoun-can-change-the-world/>
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