On Thu, Dec 14, 2017 at 7:03 PM, Guido van Rossum <gu...@python.org> wrote: > A slot is pretty expensive, as *every* class in existence will be another 8 > bytes larger (and possibly more due to malloc rounding). So unless we find > that there's a significant performance benefit I think we should hold back > on this. IIRC Ivan has already measured an order of magnitude's speedup > (well, 7x), so we may not need it. :-)
My motivation to add the slot wasn't the performance: it's just not possible to have a class-level __getitem__ on types defined in C. The only way is to define a base class in C and then extend it in pure-Python. This isn't too hard usually, though. BTW that slot could also host the new __mro_entries__ method, and, potentially, other magic methods like __subclasscheck__ and __instancecheck__. Yury _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
