New submission from Serhiy Storchaka <storchaka+cpyt...@gmail.com>:
The proposed PR refactors the implementation of typing._SpecialForm. Different special forms are different by name, docstring, and the behavior of __getitem__. Instead of special casing by name in __getitem__, instances are now parametrized by the implementation of __getitem__. _SpecialForm is now used as a decorator and takes the name and the docstring from the decorated function. It looks nicer to me now. Also removed implementations of some methods: * Inheriting from _Immutable no longer needed because __reduce__ makes instance atomic for copying. * __new__ was only needed when _SpecialForm was a subclass of type. It prevented using it as a metaclass. Now it is no longer needed. * Docstring is now assigned directly to the __doc__ slot. Previously it conflicted with the class docstring, but now the class docstring was converted into the class comment. _SpecialForm is not a public class, and pydoc shows the class comment if there is no a class docstring. * __eq__ and __hash__ are no longer needed. Instances are singletons, and comparing by identity works as well as comparing by name. They could be needed before implementing __reduce__(). * __call__ no longer needed. Instances are not callable, and the error message is good enough. The bonus -- callable() now returns False. ---------- components: Library (Lib) messages: 366817 nosy: gvanrossum, levkivskyi, serhiy.storchaka priority: normal severity: normal status: open title: Refactor typing._SpecialForm type: enhancement versions: Python 3.9 _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue40336> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
