Thanks for taking the time to write this PEP, Chris, even though I'm -1 on the idea. I'm glad to just have this as a historical document for the idea.
On Tue, 27 Feb 2018 at 22:53 Chris Angelico <ros...@gmail.com> wrote: > On Wed, Feb 28, 2018 at 4:52 PM, Robert Vanden Eynde > <robertv...@gmail.com> wrote: > > Hello Chris and Rob, > > > > did you compare your proposal tothe subject called "[Python-ideas] > Temporary > > variables in comprehensions" on this month list ? > > Yes, I did; that's one of many threads on the subject, and is part of > why I'm writing this up. > > One section that I have yet to write is "alternative syntax > proposals", which is where I'd collect all of those together. > > > If you don't want to go through all the mails, I tried to summarize the > > ideas in this mail : > > https://mail.python.org/pipermail/python-ideas/2018-February/048987.html > > > > In a nutshell one of the proposed syntax was > > > > stuff = [(y, y) where y = f(x) for x in range(5)] > > > > Or with your choice of keyword, > > > > stuff = [(y, y) with y = f(x) for x in range(5)] > > > > Your proposal uses the *reverse* syntax : > > > > stuff = [(y, y) with f(x) as y for x in range (5)] > > ... > > I wish I could write a pep to summarize all the discussions (including > > yours, my summary, including real world examples, including pro's and > > con's), or should I do a gist on GitHub so that we can talk in a more > "forum > > like" manner where people can edit their answers and modify the document > ? > > This mailing is driving me a bit crazy. > > This is exactly why I am writing up a PEP. Ultimately, it should list > every viable proposal (or group of similar proposals), with the > arguments for and against. Contributions of actual paragraphs of text > are VERY welcome; simply pointing out "hey, don't forget this one" is > also welcome, but I then have to go and write something up, so it'll > take a bit longer :) > > > As Rob pointed out, your syntax "(f(x) as y, y)" is really assymmetric > and > > "(y, y) with f(x) as y" or "(y, y) with y = f(x)" is probably prefered. > > Moreover I agree with you the choice of "with" keyword could be confused > > with the "with f(x) as x:" statement in context management, so maybe > "with x > > = f(x)" would cleary makes it different ? Or using a new keyword like > "where > > y = f(x)", "let y = f(x)" or probably better "given y = f(x)", "given" > isn't > > used in current librairies like numpy.where or sql alchemy "where". > > And also the standard library's tkinter.dnd.Icon, according to a quick > 'git grep'; but that might be just an example, rather than actually > being covered by backward-compatibility guarantees. I think "given" is > the strongest contender of the three, but I'm just mentioning all > three together. > > A new version of the PEP has been pushed, and should be live within a > few minutes. > > https://www.python.org/dev/peps/pep-0572/ > > Whatever I've missed, do please let me know. This document should end > up incorporating, or at least mentioning, all of the proposals you > cited. > > ChrisA > _______________________________________________ > Python-ideas mailing list > Python-ideas@python.org > https://mail.python.org/mailman/listinfo/python-ideas > Code of Conduct: http://python.org/psf/codeofconduct/ >
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