DIP 1022--foreach auto ref--Community Review Round 1

[Manu]

On Sat, Aug 17, 2019 at 12:58 AM Dukc via Digitalmars-d
<digitalmars-d at puremagic.com> wrote:
>
> On Friday, 16 August 2019 at 05:31:38 UTC, Manu wrote:
> > On Thu, Aug 15, 2019 at 1:16 AM Dukc via Digitalmars-d
> >> If it is not, sorry, I still don't get it.
> >
> >         void fun(ref int x)
> >         {
> >             auto y = x; // remember x
> >
> >             foreach (i; AliasSeq!(x, x))
> >             {
> >                 ++i;
> >             }
> >             assert(x == y); // only copies were incremented, x
> > is unchanged
> >
> >             static foreach (i; AliasSeq!(x, x))
> >             {
> >                 ++i;
> >             }
> >             assert(x == y + 2); // the aliased symbol 'x' was
> > incremented
> >         }
> >
>
> Yes, this works. Disregard all what I have said about `static
> foreach` over an `AliasSeq`, I obviously need to think it
> completely again.
>
> >>
> >> Okay, I'll say that `static foreach` with `auto ref` has no
> >> effect as long as compile-time lvalues are not possible, but
> >> should change the behaviour accordingly if they are possible
> >> in the future.
> >
> > Compile-time lvalues are absolutely possible, I've showed code
> > how it works a bunch of times, including just above (difference
> > between foreach and static foreach).
> >
>
> Yeah, as an `AliasSeq`, but I meant ranges and structs with an
> `opApply()` here. I know I didn't say it that way in the DIP, but
> I already agreed to change it.
>
> >> And remember, this clause does not apply to alias sequences.
> >
> > It's a bit weird to say 'except' that way; static foreach
> > primarily applies to tuples, and foreach should probably be
> > deprecated such that it can't apply to tuples.
> >
> > It's not technically wrong, but it's just seems a bit of a
> > weird way to paint that rule to me.
>
> I'll try to avoid describing it this way in the DIP, it's just
> that it was easiest to answer quote-by-quote in this theard and
> that led to my articulation of "except".

👍

I think we're on the same page now.
I'll stop hassling and let you make those tweaks :)