[Python-ideas] PEP 505: None-aware operators

[Giampaolo Rodola']

On Sun, Jul 22, 2018 at 10:55 PM Chris Angelico <rosuav at gmail.com> wrote:
>
> On Mon, Jul 23, 2018 at 6:43 AM, Giampaolo Rodola' <g.rodola at gmail.com> wrote:
> > On Sun, Jul 22, 2018 at 10:01 PM Chris Angelico <rosuav at gmail.com> wrote:
> >>
> >> On Mon, Jul 23, 2018 at 1:09 AM, Giampaolo Rodola' <g.rodola at gmail.com> wrote:
> >> > On Sun, Jul 22, 2018 at 3:38 PM Chris Angelico <rosuav at gmail.com> wrote:
> >> > I find it less explicit mainly because it does 3 things at once: check
> >> > if attribute is None, use it if it's not None and continue the
> >> > evaluation from left to right. I find that logic to be more explicit
> >> > when living on different lines or is clearly delimited by keywords and
> >> > spaces. ? has no spaces, it's literally "variable names interrupted by
> >> > question marks" and evaluation can stop at any time while scanning the
> >> > line from left to right. Multiple "?" can live on the same line so
> >> > that's incentive to write one-liners, really, and to me one-liners are
> >> > always less explicit than the same logic split on multiple lines.
> >>
> >> Ah, I see what you mean. Well, think about what actually happens when
> >> you write "lst.sort()". In terms of "hidden behaviour", there is far
> >> FAR more of it in existing syntax than in the new proposals.
> >
> > I am not sure I'm following you (what does lst.sort() have to do with "?"?).
>
> The "." in "lst.sort" is an operator. How much hidden behaviour is
> there in that? Do you actually even know every possible thing that can
> happen? Don't feel bad if you don't - it's not an indictment of your
> quality as a programmer, but an acknowledgement that Python's
> attribute access is incredibly complicated.

I'm going to engage into a discussion about the analogy between "?"
and "." because simply there is none. It doesn't prove anything except
that you're not really interested in having a serious discussion about
the pros and cons of this PEP: you just want it to happen no matter
what.

> Imagine if we were talking about people, rather than features in a
> language; imagine if, to join the Warriors Guild, you had to first
> slay a red dragon with nothing but a rusty dagger, despite none of the
> existing members having done so. Is that reasonable to ask? Can you
> say "well, the guild is mature now, so yeah, it's a good thing"?

Ditto.

-- 
Giampaolo - http://grodola.blogspot.com