On Oct 28, 2019, at 14:23, Serhiy Storchaka <storch...@gmail.com> wrote: > > 28.10.19 20:38, Andrew Barnert via Python-ideas пише: >> Many of them are abusing throw(StopIteration) to fake a “takewhile clause” >> in comprehensions > > Well, so actually you needed the break expression. Or multistatement > comprehension.
Well, what I really (thought I) needed was a more concise way to do the equivalent of takewhile and friends, and I still think the ideal solution there is a general way to write concise lambdas or the equivalent using a great new syntax that nobody has been able to come up with yet in any of the times the idea has been discussed. :) Faking it by raising StopIteration in the middle of the value expression or an if clause seemed like a clever workaround, albeit only for takewhile. But it actually has a lot of problems; various things that shouldn’t change your semantics do if you’re using this hack. (For example, chain up a few throw-breaking genexprs, then change one of the intermediate ones to a listcomp so you can see it in the debugger.) So, I’d already abandoned it before the PEP that broke it. Would a break expression be able to give me the same benefits without the problems? Maybe. But I honestly haven’t missed the throw(StopIteration) hack enough to experiment with that idea when people suggested it. _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/OAF4DXJQKUVQSK4MCKRZLFKJWVN6OGTR/ Code of Conduct: http://python.org/psf/codeofconduct/
