Can't understand templates

[Ali Çehreli via Digitalmars-d-learn]

On 11/29/2014 10:19 AM, Sly wrote:

 > You miss another definition which introduces a conflict:
 > T getResponse(T)(string question)
 > {...}

The following works with dmd git head:

import std.stdio;

T getResponse(T)(string question)
{
     writef("%s (%s): ", question, T.stringof);

     T response;
     readf(" %s", &response);

     return response;
}

class Pair(A, B) {
       A a;
       B b;
       this(A a, B b) {this.a = a; this.b = b;}
}

Pair!(A, B) getResponse(P : Pair!(A, B), A, B)(string question)
{
     writeln(question);
      auto a = getResponse!A(" a");
      auto b = getResponse!B(" b");
      return new Pair!(A, B)(a, b);
}

struct Point(T)
{
     T x;
     T y;
}

Point!T getResponse(P : Point!T, T)(string question)
{
     writefln("%s (Point!%s)", question, T.stringof);

     auto x = getResponse!T("  x");
     auto y = getResponse!T("  y");

     return Point!T(x, y);
}

void main()
{
     auto number = getResponse!int("number?");
     writeln(number);

     auto pair = getResponse!(Pair!(int, long))("pair?");
     writeln(pair);

     auto point = getResponse!(Point!int)("point?");
     writeln(point);
}

Ali