Andrew Barnert added the comment: > I don’t think you need to define __len__() to get an iterable, only > __getitem__().
The "old-style sequence protocol" means having a __getitem__ that works for values from 0 to __len__() and raises IndexError at __len__(). You don't need to be a complete old-style sequence to be iterable; just having __getitem__ makes you iterable (without being a collections.abc.Iterable or a typing.Iterable), and having __getitem__ and __len__ makes you reversible (without being a typing.Reversible). At any rate, this bug isn't about avoiding false negatives for the implicit ABCs, but false positives: defining __iter__ = None blocks the old-style sequence protocol, but makes isinstance(Iterable) true. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue25958> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
