• andre (28/28) Oct 08 2014 Hi,
• anonymous (43/71) Oct 08 2014 As far as I can tell, 'this' parameters don't work with static
• andre (4/83) Oct 08 2014 Thanks a lot for the helpful explanation.

"andre" <andre s-e-a-p.de> writes:

Hi,

could you check whether it is correct, that second line in main
failes with a compiler error?
I think the compiler should be able to deduce the type without
explicitly passing it to the method call.

Kind regards
André

template ClassTemplate()
{
   static auto deserialize(this MyType)()
   {
     return new MyType();
   }
}

class A
{
   mixin ClassTemplate;
}

void main()
{
   A a = A.deserialize!A(); // Working
   A b = A.deserialize(); // Not working
}

source\app.d(17): Error: template 
app.A.ClassTemplate!().deserialize cannot dedu
ce function from argument types !()(), candidates are:
source\app.d(3):        app.A.ClassTemplate!().deserialize(this 
MyType)()

"anonymous" <anonymous example.com> writes:

On Wednesday, 8 October 2014 at 10:36:33 UTC, andre wrote:
 Hi,

 could you check whether it is correct, that second line in main
 failes with a compiler error?
 I think the compiler should be able to deduce the type without
 explicitly passing it to the method call.

 Kind regards
 André

 template ClassTemplate()
 {
   static auto deserialize(this MyType)()
   {
     return new MyType();
   }
 }

 class A
 {
   mixin ClassTemplate;
 }

 void main()
 {
   A a = A.deserialize!A(); // Working
   A b = A.deserialize(); // Not working
 }

 source\app.d(17): Error: template 
 app.A.ClassTemplate!().deserialize cannot dedu
 ce function from argument types !()(), candidates are:
 source\app.d(3):        app.A.ClassTemplate!().deserialize(this 
 MyType)()

As far as I can tell, 'this' parameters don't work with static
methods. You can use typeof(this) instead:

----
template ClassTemplate()
{
    static auto deserialize()
    {
      return new typeof(this)();
    }
}

class A
{
    mixin ClassTemplate;
}

void main()
{
    A b = A.deserialize();
}
----

Be aware of the difference between template 'this' parameters and
typeof(this). A 'this' parameter is set to the (static) type of
the object, while typeof(this) is always the type of the
surrounding class.

----
class A
{
    import std.stdio;
    void printTypeofThis() {writeln(typeof(this).stringof);}
    void printThisParameter(this T)() {writeln(T.stringof);}
}

class B : A {}

void main()
{
    auto b = new B;
    b.printTypeofThis(); /* "A", because the method is in A */
    b.printThisParameter(); /* "B", because b is a B (statically) 
*/
    A a = b;
    a.printThisParameter(); /* "A", because a is an A (statically)
*/
}
----

"andre" <andre s-e-a-p.de> writes:

Thanks a lot for the helpful explanation.

Kind regards
André

On Wednesday, 8 October 2014 at 21:10:02 UTC, anonymous wrote:
 On Wednesday, 8 October 2014 at 10:36:33 UTC, andre wrote:
 Hi,

 could you check whether it is correct, that second line in main
 failes with a compiler error?
 I think the compiler should be able to deduce the type without
 explicitly passing it to the method call.

 Kind regards
 André

 template ClassTemplate()
 {
  static auto deserialize(this MyType)()
  {
    return new MyType();
  }
 }

 class A
 {
  mixin ClassTemplate;
 }

 void main()
 {
  A a = A.deserialize!A(); // Working
  A b = A.deserialize(); // Not working
 }

 source\app.d(17): Error: template 
 app.A.ClassTemplate!().deserialize cannot dedu
 ce function from argument types !()(), candidates are:
 source\app.d(3):        
 app.A.ClassTemplate!().deserialize(this MyType)()

 As far as I can tell, 'this' parameters don't work with static
 methods. You can use typeof(this) instead:

 ----
 template ClassTemplate()
 {
    static auto deserialize()
    {
      return new typeof(this)();
    }
 }

 class A
 {
    mixin ClassTemplate;
 }

 void main()
 {
    A b = A.deserialize();
 }
 ----

 Be aware of the difference between template 'this' parameters 
 and
 typeof(this). A 'this' parameter is set to the (static) type of
 the object, while typeof(this) is always the type of the
 surrounding class.

 ----
 class A
 {
    import std.stdio;
    void printTypeofThis() {writeln(typeof(this).stringof);}
    void printThisParameter(this T)() {writeln(T.stringof);}
 }

 class B : A {}

 void main()
 {
    auto b = new B;
    b.printTypeofThis(); /* "A", because the method is in A */
    b.printThisParameter(); /* "B", because b is a B 
 (statically) */
    A a = b;
    a.printThisParameter(); /* "A", because a is an A 
 (statically)
 */
 }
 ----