At this point, the fact that several Python core developers fail to understand the pieces of code presented as examples should be a hint that the syntax here is far from desirable...
Regards Antoine. On Sat, 25 Nov 2017 15:47:14 +0000 Paul Moore <p.f.mo...@gmail.com> wrote: > On 25 November 2017 at 14:55, Ivan Levkivskyi <levkivs...@gmail.com> wrote: > > Continuing the topic of the ban, what exactly should be banned? For example > > will this still be valid? > > > > def pack_two(): > > return [(yield), (yield)] # Just a list display > > > > I don't see how this is controversial. It is clear that `pack_two` is a > > generator. > > It's not clear to me... > > Seriously, I wouldn't know what this would do. Presumably it needs > someone calling send() to generate results (because that's now yield > expressions work) but beyond that, I don't really understand what it > does. Maybe an example that wasn't artificial would be more obvious, > I'm not sure. > > > If this is going to be prohibited, then one may be surprised by lack of > > referential transparency, since this will be valid: > > > > def pack_two(): > > first = (yield) > > second = (yield) > > return [first, second] > > The fact that you can't inline first and second doesn't bother me. I > can't fully explain why, but it doesn't. (Technically, I *can* explain > why, but you'd disagree with my explanation :-)) > > > If the first example will be allowed, then one will be surprised why it > > can't be rewritten as > > > > def pack_two(): > > return [(yield) for _ in range(2)] > > > > I have found several other examples where it is not clear whether they > > should be prohibited with `yield` or not. > > So far, none of your examples have demonstrated anything that Guido's > suggestion to ban yield would make confusing *to me*. > > Maybe this demonstrates nothing more than how inconsistent and shallow > my understanding of yield expressions is. That's fine, I can live with > that. I can't give you any assurances that my level of understanding > is common among non-experts, but I will say that in my view, Guido's > proposal feels sensible and intuitive. And after all, if the use of > yield expressions becomes significantly more common, and the general > level of familiarity with the concept increases, it's easy enough to > relax the restriction later, in line with the average user's level of > comfort. > > Paul _______________________________________________ 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
