> On 26 Jun 2019, at 16:46, Chris Angelico <ros...@gmail.com> wrote: > >> On Thu, Jun 27, 2019 at 12:37 AM Anders Hovmöller <bo...@killingar.net> >> wrote: >> >>>> On 26 Jun 2019, at 14:28, Rhodri James <rho...@kynesim.co.uk> wrote: >>>> >>>> On 26/06/2019 08:34, Yanghao Hua wrote: >>>> I find the objection reasoning very strange as none of the default >>>> behavior changed, and yet if you use this feature you do need to worry >>>> about the object behavior regarding assignment, this is true for >>>> descriptors and all other magics. >>> >>> The problem is not the default behaviour. The problem is that the average >>> reader of your code cannot know that something that appears to be an >>> ordinary assignment has been redefined elsewhere to be something entirely >>> herring. Your code stops being understandable to other people. >> >> I 100% agree that this proposal is a bad idea. But I do have to play Devils >> advocate here. >> >> The the-code-is-understandable-at-face-value ship has already sailed. + >> doesn't mean add, it means calling a dunder function that can do anything. >> Foo.bar = 1 doesn't mean set bar to 1 but calling a dunder method. In python >> code basically can't be understood at face value. >> > > There are many things that can be implemented with dunders, yes, but > in Python, I would expect these two functions to behave identically: > > def f1(x): > return frob(x).spam > > def f2(x): > f = frob(x) > s = f.spam > return s > > This correlation is critical to sane refactoring. You should be able > to transform f1 into f2, and then insert print calls to see what 'f' > and 's' are, without affecting the behaviour of the function. The > proposed magic would change and completely break this; and as such, it > violates programmer expectations *across many languages* regarding > refactoring.
I'm out of the game for many years but isn't that potentially extremely different in C++ for example? / Anders _______________________________________________ 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/YMHEUHBCRNN6PEAPOTA6NWBKB5GCPKJS/ Code of Conduct: http://python.org/psf/codeofconduct/
