Testing for template argument being result of takeExactly

[Timon Gehr]

On 09/24/2012 09:41 AM, monarch_dodra wrote:
> ...
>
> Regarding the ".init" issue, I hadn't thought of that, but it can
> be worked around pretty easily with an is(R r):
>
> --------
> template Hello(R)
>       if ( is(R r) &&
>            is(typeof(takeExactly(r, 1))) &&
>            is(R == typeof(takeExactly(r, 1)))
>       )
> {
>       alias R Hello;
> }
> --------
> After that, I guess it is indeed one implementation detail vs the
> other.
>

I don't think this does what you think it does. The 'is(R r)' declares r 
to be an alias for R. So 'r' is a type in that code snippet.

Also, is(typeof(takeExactly(R, 1))) && is(R == typeof(takeExactly(R, 1)))

can be written in a more compact way as

is(typeof(takeExactly(R, 1)) == R)


> IMO, it really depends on whether or not you'd want "int[]" to be
> considered the return type of a takeExactly :/ Maybe it is, maybe
> it ain't.