On Sun, Nov 28, 2021 at 04:40:15PM -0800, Christopher Barker wrote: > Sure, but I"m not sure it's THAT much harder to say: > > If you want to make an iterator, define a __next__ method.
Just for the record, that's not what makes an iterator. That makes a half-and-half something almost but not quite an iterator :-) To be an iterator, your object needs: 1. a `__next__` method which returns the next value; 2. and an `__iter__` method which returns self. Also we do often use the term "iterator" informally to refer to objects which have an `__iter__` method which returns an iterator. > If you want to make a ChainableIterator, derive from abc.ChaibableIterator > -- it will give you some nifty stuff for free. Pythonistas: "Duck typing for the win! You shouldn't care about inheritence, protocols are better!" Also Pythonistas: "Just inherit from X." *wink* > And some of the current ABCs do provide some out of the box functionality > right now. > > It would take someone other than me to explore this idea further, I'm not > sure I even want it. But it struck me that one of the reasons we don't want > to add functionality to existing ABCs is that it would suddenly make other > types that currently conform to the ABC, but don't derive from it, no > longer valid. ANd with the proliferation of type checking, that would be a > mess. I think that is correct. > But if we create a new ABC that extends an existing protocol, it wouldn't > break anything. Except that way leads to a thousand ABCs, which is another sort of chaos: - Container - Container_With_Spam - Container_With_Spam_Eggs - Container_With_Spam_Eggs_DoubleSpam_and_Spam - Container_With_Spam_Eggs_DoubleSpam_and_Spam_and_Cheese - Container_With_Spam_Eggs_DoubleSpam_and_Spam_and_Cheese_Without_Eggs -- Steve _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/HESFVOAH5HZUUAR3YGM7OLGBX3FA4DR4/ Code of Conduct: http://python.org/psf/codeofconduct/
