Tuples

[dsimcha]

== Quote from BCS (ao at pathlink.com)'s article
> Reply to dsimcha,
> > I've been thinking a little about the idea of returning tuples from
> > functions, w.r.t. Bugzilla 2628
> > (http://d.puremagic.com/issues/show_bug.cgi?id=2628).   Would it be
> > feasible to solve this by making struct[index] for any struct w/o an
> > opIndex overload equivalent to struct.tupleof[index]?  This would be
> > trivial syntactic sugar, but would allow user-defined tuples in Phobos
> > to look like a builtin tuple, be returned from functions, etc., while
> > changing very little under the hood.   Furthermore, for functions that
> > take a tuple, we could allow structs to be implicitly cast to tuples,
> > e.g.:
> >
> > struct Foo {
> > uint u;
> > float f;
> > }
> > void doStuff(uint myInt, float myFloat) {}
> >
> > Foo foo;
> > doStuff(foo);  // Implicitly casts to foo.tupleof, works.
> I like the first part some (but not without reservations). As for the second
> bit... I don't like it. It would make overload resolution to tricky, if not
> at the compiler level than at the eyeball level.

Yeah, scratch the second part.  In addition, I thought of this problem after I posted:

struct Foo {
    uint u;
    float f;
}

void doStuff(T...)(T args) {}
Foo foo;
doStuff(foo);  // Ambiguous.  Does the struct get passed, or is it //unpacked to a
tuple?