• Zarathustra (48/48) Oct 22 2009 I would like to know, how to override function if subclass and super cla...
• grauzone (3/60) Oct 22 2009 It's a bug. package functions are never virtual, and the "override"
• Zarathustra (20/81) Oct 22 2009 In my opinion 'private' shouldn't be virtual if sub- and sup- classes ar...

Zarathustra <adam.chrapkowski gmail.com> writes:

I would like to know, how to override function if subclass and super class are
located in the same package and different modules.

For instance when they are in the same module:
//___________________________________
module main;
class Foo{

  this(){
    proc();
  }
  
  void proc(){
    writefln("Foo");
  }
}

class Bar : Foo{
  override void proc(){
    writefln("Bar");
  }
}

void main(){
  new Bar;
}
//___________________________________
the result is "Bar" so it's great, but:

//___________________________________
module pack.foo;

class Foo{

  this(){
    proc();
  }
  
  package void proc(){ // without 'package' it works well
    writefln("Foo");
  }
}

//___________________________________
module pack.bar;

class Bar : Foo{
  package override void proc(){ // without 'package' it works well
    writefln("Bar");
  }
}
//___________________________________
module main;
void main(){
  new Bar;
}
//___________________________________
the result is "Foo" so it's unexpected to me.

grauzone <none example.net> writes:

Zarathustra wrote:
 I would like to know, how to override function if subclass and super class are
located in the same package and different modules.
 
 For instance when they are in the same module:
 //___________________________________
 module main;
 class Foo{
 
   this(){
     proc();
   }
   
   void proc(){
     writefln("Foo");
   }
 }
 
 class Bar : Foo{
   override void proc(){
     writefln("Bar");
   }
 }
 
 void main(){
   new Bar;
 }
 //___________________________________
 the result is "Bar" so it's great, but:
 
 //___________________________________
 module pack.foo;
 
 class Foo{
 
   this(){
     proc();
   }
   
   package void proc(){ // without 'package' it works well
     writefln("Foo");
   }
 }
 
 //___________________________________
 module pack.bar;
 
 class Bar : Foo{
   package override void proc(){ // without 'package' it works well
     writefln("Bar");
   }
 }
 //___________________________________
 module main;
 void main(){
   new Bar;
 }
 //___________________________________
 the result is "Foo" so it's unexpected to me.

It's a bug. package functions are never virtual, and the "override" 
attribute is just ignored. Same with private. Welcome to D.

Zarathustra <adam.chrapkowski gmail.com> writes:

grauzone Wrote:

 Zarathustra wrote:
 I would like to know, how to override function if subclass and super class are
located in the same package and different modules.
 
 For instance when they are in the same module:
 //___________________________________
 module main;
 class Foo{
 
   this(){
     proc();
   }
   
   void proc(){
     writefln("Foo");
   }
 }
 
 class Bar : Foo{
   override void proc(){
     writefln("Bar");
   }
 }
 
 void main(){
   new Bar;
 }
 //___________________________________
 the result is "Bar" so it's great, but:
 
 //___________________________________
 module pack.foo;
 
 class Foo{
 
   this(){
     proc();
   }
   
   package void proc(){ // without 'package' it works well
     writefln("Foo");
   }
 }
 
 //___________________________________
 module pack.bar;
 
 class Bar : Foo{
   package override void proc(){ // without 'package' it works well
     writefln("Bar");
   }
 }
 //___________________________________
 module main;
 void main(){
   new Bar;
 }
 //___________________________________
 the result is "Foo" so it's unexpected to me.

 
 It's a bug. package functions are never virtual, and the "override" 
 attribute is just ignored. Same with private. Welcome to D.

In my opinion 'private' shouldn't be virtual if sub- and sup- classes are
located in different modules. Also if I have a global private function in the
first module and the global function at the same name in the second module
there shouldn't be conflict.

In C++ everything which is in 'source file', but not in 'header' it is nothing
less than 'private'. I D it is impossible to 'hide' global function inside
module (in my opinion it is bug).

I resolved 'package' function overriding problem as follow:

class Foo{
  package void delegate() proc;
  private void _proc(){ ... }
  this(){
    proc = &_proc;
  }
  package this(void delegete() o_proc){
    proc = o_proc;
  }
}

class Bar : Foo{
  private void _proc(){ ... }
  this(){
    super(&_proc);
  }
}