• David Nadlinger (32/32) Nov 21 2009 In a wrapper generator I am writing, I need to check if some member func...
• div0 (18/23) Nov 21 2009 -----BEGIN PGP SIGNED MESSAGE-----

David Nadlinger <david.nadlinger gmail.com> writes:

In a wrapper generator I am writing, I need to check if some member function 
foo() has been overridden in a subclass.

Thanks to the help of maxter at #d, I currently have this for D1:

template addressOf( alias fn ) {
  const addressOf = &fn;
}

class A {
  void foo() {}

  final void bar() {
    auto dg = &foo;
    if ( addressOf!( foo ) == dg.funcptr ) {
      Stdout( "not overridden" ).newline;
    } else {
      Stdout( "overridden" ).newline;
    }
  }
}

class B : A {
  override void foo() {}
}

void main() {
  A a = new A();
  a.bar;

  A b = new B();
  b.bar;
}

Although the code works fine with DMD, LDC complains that »this« is needed 
to evaluate &foo in addressOf. Is this a bug in LDC or in fact illegal code 
which DMD happens to erroneously accept? Are there any less hackish ways to 
perform the check?

Thanks,
klickverbot

div0 <div0 users.sourceforge.net> writes:

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David Nadlinger wrote:
 Although the code works fine with DMD, LDC complains that »this« is needed 

 to evaluate &foo in addressOf.

That looks like a ldc bug. &foo is occurring in a normal method so it
does have 'this'.

 Is this a bug in LDC or in fact illegal code
 which DMD happens to erroneously accept? Are there any less hackish ways to 
 perform the check?

Not with D1 I think.

D2 has traits to help with this sort of thing.
http://www.digitalmars.com/d/2.0/traits.html

- --
My enormous talent is exceeded only by my outrageous laziness.
http://www.ssTk.co.uk
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