Re: [fpc-pascal] How to use generics and meta class?

[Sven Barth]

Am 25.02.2014 00:27, schrieb silvioprog:
Hello,
I have this structure:

  generic TMyGeneric<T> = class
  end;

  TMyGenericClass = class of TMyGeneric;

  TMyType = class
  end;

  TMyClass1 = specialize TMyGeneric<TMyType>;

  TMyClass2 = class(specialize TMyGeneric<TMyType>)
  end;

...

procedure RegisterItem(AItemClass: TMyGenericClass);
begin
end;

OK, but when I try:

RegisterItem(TMyClass1);

Return:

Incompatible type for arg no. 1: Got "Class Of TMyGeneric$TMyType", 
expected "TMyGenericClass".

Or:

RegisterItem(TMyClass2);

Return:

Incompatible type for arg no. 1: Got "Class Of TMyClass2", expected 
"TMyGenericClass"

So, which syntax to use generic and meta class?

What might work (untested) is this:

=== code begin ===

type
  generic TMyGeneric<T> = class
  public type
    TMyGenericClass = class of TMyGeneric; // in mode Delphi this would 
be "class of TMyGeneric<T>"
  public
    class procedure RegisterItem(aItemClass: TMyGenericClass);
  end;

=== code end ===

Regards,
Sven
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