On Thu, 20 Jul 2017 21:29:18 +0900 INADA Naoki firstname.lastname@example.org wrote:
WeakSet should be cared specially. Maybe, ABCMeta can be optimized first.
Currently, ABCMeta use three WeakSets. But it can be delayed until `register` or `issubclass` is called. So even if WeakSet is implemented in Python, I think ABCMeta can be much faster.
Simple uses of WeakSet can probably be replaced with regular sets + weakref callbacks. As long as you are not doing one of the delicate things (such as iterate), it should be fine.