On Fri, Jan 17, 2014 at 05:29:14PM +0000, Gary Willoughby wrote:
> On Friday, 17 January 2014 at 15:56:46 UTC, H. S. Teoh wrote:
> >Couldn't you just return a Variant? I thought this is what Variants
> >are made for.
> >
> >
> >T
>
> Yes but then i would need to coerce it to get it's underlying type.
But isn't that what you'd have to do anyway? I mean, how else would the
following code work?
class DynClass {
...
auto opDispatch(string field)() {
return dotDotDotMagic();
}
}
void main(string[] args) {
auto d = new DynClass();
if (args[1] == "int")
d.abc = 123; // d.abc = int
else
d.abc = "xyz"; // d.abc = string
// Suppose this somehow works:
auto x = d.abc; // what's the type of x?
}
Since the type of x must be known at compile-time, but the type of d.abc
can't be known until runtime, the above code can't possibly work unless
d.abc returns a Variant. It's simply not possible for a
runtime-determined type to be put into a variable of compile-time
determined type without some kind of runtime check.
Now I'm not sure if Variant allows assignment to a static type, but in
theory this should be possible:
// assume d.abc returns a Variant
int x = d.abc; // will assert if d.abc doesn't hold an int at runtime
T
--
There are 10 kinds of people in the world: those who can count in binary, and
those who can't.
