Just where has this language gone wrong?

[Simen Kjaeraas]

On Tue, 24 Jul 2012 13:00:44 +0200, Jonathan M Davis <jmdavisProg at gmx.com>  
wrote:

> On Tuesday, July 24, 2012 11:03:16 Simen Kjaeraas wrote:
>> On Tue, 24 Jul 2012 04:21:18 +0200, Andrei Alexandrescu
>>
>> <SeeWebsiteForEmail at erdani.org> wrote:
>> >> Tuple!(float, "x", float, "y") bar() {
>> >> return typeof(return)( 0.0, 0.0 );
>> >> }
>>
>> [snip]
>>
>> > We could make
>> >
>> > return tuple(0.0, 0.0);
>> >
>> > to work. I can't imagine a scenario in which this relaxation would  
>> cause
>> > a bug.
>>
>> I would argue it should work, for the exact reasons outline above. And  
>> as
>> you say, it should cause no bugs.
>>
>> But can it be made to work in current D, as a library solution? Or do  
>> you
>> mean the language should be changed? (This looks to me a lot like the  
>> old
>> opImplicitCast)
>
> That's what alias this is for.

Well, sorta. See, I'm asking for an unbounded set of possible
conversions, as Tuple!int should be implicitly convertible to
Tuple!(int, "a"), Tuple!(int, "b"), Tuple!(int, "Help"), and
Tuple!(int, "AnotherOneBitesTheDust").

And that's just the ones with int as the first parameter. Then comes
float, double, long, and so on.

I may be wrong, but I don't think alias this can handle that. In fact,
I just tried, and got DMD to hang.

-- 
Simen