2018-07-05 15:14 GMT+02:00 Gustavo Carneiro <gjcarne...@gmail.com>: > I don't know if you're trying to propose something clever here, like "if (x > := func()):" would assign to 'x' only inside the "then" body of the if, but > IMHO that would be a terrible idea:
I don't propose to change the PEP 572. I'm trying to explain to myself where "if (var := expr): ..." would add anything to readers compared to "var = expr; if var: ...". I know that var is still valid after the if. I'm not asking to raise a syntax error or even emit a linter warning if var is used after the if. I'm just thinking loudly where the PEP 572 is appropriate. IMHO the following code should not use assignement expression. Good: help = self._root_section.format_help() if help: help = self._long_break_matcher.sub('\n\n', help) help = help.strip('\n') + '\n' return help Bad? if (help := self._root_section.format_help()): help = self._long_break_matcher.sub('\n\n', help) help = help.strip('\n') + '\n' return help IHMO using "help :=" here would send the wrong signal to the reader: as if help is not going to be used after the if, whereas it's the case ("return help"). Victor _______________________________________________ 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