TZblok

Našel jsem ve Wikipedii (pro mě) podivný termín: Duck typing. Tak mě zajímalo co to je a jestli by to šlo implementovat v Delphi. Zde je výsledek:

/// This is example of duck typing in Delphi.

/// Based on: http://en.wikipedia.org/wiki/Duck_typing



program DuckTyping;



{$APPTYPE CONSOLE}



uses ObjComAuto;



{$METHODINFO ON} // important



type

 TDuck = class

 public

   procedure Quack;

   procedure Feathers;

 end;



 TPerson = class

 public

   procedure Quack;

   procedure Feathers;

 end;



procedure TDuck.Quack;

begin

 Writeln('Quaaaaaack!');

end;



procedure TDuck.Feathers;

begin

 Writeln('The duck has white and gray feathers.');

end;



procedure TPerson.Quack;

begin

 Writeln('The person imitates a duck.');

end;



procedure TPerson.Feathers;

begin

 Writeln('The person takes a feather from the ground and shows it.');

end;



procedure InTheForest(V: Variant);

begin

 V.Quack;

 V.Feathers;

end;



procedure Game;

var

 Duck, Person: Variant; // or IDispatch

begin

 Duck := TObjectDispatch.Create(TDuck.Create, True) as IDispatch;

 Person := TObjectDispatch.Create(TPerson.Create, True) as IDispatch;

 InTheForest(Duck);

 InTheForest(Person);

end;



begin

 Game;

end.

Štítky: Delphi