Declaring Ref Variables Inside Function Calls

[Bill Baxter]

On Wed, Apr 1, 2009 at 5:03 AM, Sergey Gromov <snake.scaly at gmail.com> wrote:
>
> Tue, 31 Mar 2009 12:18:21 -0700, Andrei Alexandrescu wrote:
>
> > Jarrett Billingsley wrote:
> >> On Tue, Mar 31, 2009 at 1:32 PM, Andrei Alexandrescu
> >> <SeeWebsiteForEmail at erdani.org> wrote:
> >>> Jarrett Billingsley wrote:
> >>>> 2009/3/30 dsimcha <dsimcha at yahoo.com>:
> >>>>> // How it works now:
> >>>>> uint foo;
> >>>>> string bar;
> >>>>> unpack(foo, bar) = someFunction();
> >>>>>
> >>>>> // vs. how I want it to work:
> >>>>> unpack(auto foo, auto bar) = someFunction();
> >>>> Cute, but uh, I'd much rather see tuples just be returnable.
> >>> They are.
> >>
> >> template Tuple(T...)
> >> {
> >>      alias T Tuple;
> >> }
> >>
> >> Tuple!(int, float) foo()
> >> {
> >>      return Tuple!(3, 4.5);
> >> }
> >>
> >> foo.d(10): Error: functions cannot return a tuple
> >>
> >> Unless you're using some prerelease compiler, they are not.
> >
> > import std.typecons;
> >
> > Tuple!(int, float) foo()
> > {
> >      return tuple(2, 4.5);
> > }
> >
> > The addition of the alias this feature and of constructor templates
> > makes std.typecons.Tuple even better.
> >
> > Andrei
>
> Unfair---std.typecons.Tuple is actually a struct!
>
> Well, basically struct is a run-time tuple, anyway.
>
> I think that all the buzz around "actual tuple support" boils down to
> requests for syntax sugar for construction and decomposition of
> anonymous structs.  While typecons.Tuple is sorta OK for construction,
> things are still pretty ugly on the "decomposition" end.

Right.  In my ideal world I could use tuples like this:

(int,float) a;

a = returns_tuple();

a[0] = 2;
a[1] = 3.4;

(int,float) z = returns_tuple();

(int x, float y) = returns_tuple();

auto tup = (2, 3.4);

takes_int_and_float(unpack!(tup));

I think experience with tuples in Python and ML (and probably
elsewhere -- heck even D) shows that tuples are incredibly useful.  So
useful that they deserve better syntax than Tuple!(...).

--bb