The problem here is not whether it's explicit. It's about Readability and conciseness. Using symbols in place of words almost always harms readability in favor of conciseness.
value = person.name if person.name else person almost reads like english (aside from being a weird and totally uncommon use case) value = person?.name Is a huge step towards the concise illegible soup of symbols that Perl is famous for. It's a huge No from me. On Wed, Jul 25, 2018 at 11:12 AM, Nicholas Chammas < nicholas.cham...@gmail.com> wrote: > On Mon, Jul 23, 2018 at 6:05 PM Giampaolo Rodola' <g.rod...@gmail.com> > wrote: > >> This: >> >> v = a?.b >> >> ...*implicitly* checks if value is not None [and continues execution]. >> This: >> >> v = a >> if a.b is not None: >> v = a.b >> >> ...*explicitly* checks if value is not None and continues execution. >> > > I think both of those are equally explicit. It's just that one notation is > more concise than the other. Explicitness and conciseness are related but > different things. > > When something is "explicit", as I understand it, that means it does what > it says on the cover. There is no unstated behavior. The plain meaning of > `v = a?.b` is that it expands to the longer form (`v = a; if a.b ...`), and > it is just as explicit. > > This reminds me of something I read about once called Stroustrup's Rule > <https://thefeedbackloop.xyz/stroustrups-rule-and-layering-over-time/> > [1]: > > > For new features, people insist on LOUD explicit syntax. > > For established features, people want terse notation. > > I think the "explicit vs. implicit" part of this discussion is probably > better expressed as a discussion about "loud vs. terse" syntax. None of the > operators in PEP 505 have implicit behavior, to the best of my > understanding. It's just that the operators are new and have terse > spellings. > > As a point of comparison, I think a good example of implicit behavior is > type coercion. When you ask Python to add an int to a float > > a = 3 + 4.5 > > all that you've explicitly asked for is the addition. However, Python > implicitly converts the 3 from an int to a float as part of the operation. > The type conversion isn't anywhere "on the cover" of the + operator. It's > implicit behavior. > > [1] Bjarne Stroustrup makes the observation in this talk > <https://channel9.msdn.com/Events/Lang-NEXT/Lang-NEXT-2014/Keynote> at > 23:00. > > _______________________________________________ > 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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