On 11/29/2014 12:41 AM, Sly wrote:
Ah, now I see. In C++ we would also need to supply template
parameters, but we'd put them before return type
(template<typename T> getResponse<Point<T>>); in D we put them
before the colon.
Now I'm trying to write a specialization for Pair. It seems that
this is the way to do it:
Pair!(A, B) getResponse(A, B: Pair!(A, B))(string question)
{
auto a = getResponse!A(" a");
auto b = getResponse!B(" b");
return new Pair!(A, B)(a, b);
}
auto pair = getResponse!(Pair!(int, int))("pair?");
But it doesn't work: this call resolves to a general version T
getResponse(T), and I get a compilation error because it tries to
instantiate readf!(Pair*).
What am I doing wrong?
I wish I could formalize these definitions better or consistently but
here my "art", which works: :)
Pair!(A, B) getResponse(P : Pair!(A, B), A, B)(string question)
{
// ...
}
That template parameter reads:
- This template takes a single parameter (P)
- P must match Pair!(A, B)
- Where A and B are both types
So, getting back to Point, now the following is consistent with the above:
Point!T getResponse(P : Point!T, T)(string question)
{
// ...
}
Now, that means: "This is a specialization for P, where it matches
Point!T and T is a type."
Maybe I should change the specialization examples in that chapter...
Ali
