• Daniel Ribeiro Maciel (20/20) Dec 04 2009 Hello!
• bearophile (15/15) Dec 04 2009 Daniel Ribeiro Maciel:
• Daniel Ribeiro Maciel (18/39) Dec 04 2009 Heya!
• Daniel Ribeiro Maciel (15/63) Dec 05 2009 The strange part is that, for some reason, this works:
• bearophile (5/10) Dec 05 2009 I hope the the future real static foreach will work on enum (constant) a...
• Trass3r (6/14) Jan 02 2010 __traits is a really immature thing.

Daniel Ribeiro Maciel <daniel.maciel gmail.com> writes:

Hello!

I'm trying to use __traits in the following manner:

import std.stdio;
import std.traits;

class Foo
{
    void bla() {  }
    void foo() {  }
}

int main()
{
    immutable string members[] = [ "bla", "foo" ];
    writeln( typeid(typeof(__traits(getVirtualFunctions, Foo, members[0]) )) );
}

But this won't compile. The error:

main.d(14): Error: string expected as second argument of __traits
getVirtualFunctions instead of members[0u]

What can I do? I'm trying to hack the dmd source code in order to fix this. 
Can anyone give me any tips on what to do?

Best regards,
Daniel

bearophile <bearophileHUGS lycos.com> writes:

Daniel Ribeiro Maciel:

Try this:

import std.stdio: writeln;

class Foo {
    float bla() { return 0.0; }
    void foo() {}
}

void main() {
    enum string[] members = ["bla", "foo"];
    writeln( typeid(typeof(__traits(getVirtualFunctions, Foo, members[0]) )) );
}

Output: (float())
You need enum there, unfortunately. Also note the position of [], the lack of
traits import, the qualified import from std.stdio, the void return of main,
and so on.

Bye,
bearophile

Daniel Ribeiro Maciel <daniel.maciel gmail.com> writes:

Heya!

Ok, let me explain what I want to do:


 import std.stdio: writeln;
 
 class Foo {
     float bla() { return 0.0; }
     void foo() {}
 }
 
 void main() {
     enum string[] members = __traits(allMembers, Foo );
     foreach( member; members )
         writeln( typeid(typeof(__traits(getVirtualFunctions, Foo, member) )) );
}

Is that possible?

Best regards,
Daniel


bearophile Wrote:

 Daniel Ribeiro Maciel:
 
 Try this:
 
 import std.stdio: writeln;
 
 class Foo {
     float bla() { return 0.0; }
     void foo() {}
 }
 
 void main() {
     enum string[] members = ["bla", "foo"];
     writeln( typeid(typeof(__traits(getVirtualFunctions, Foo, members[0]) )) );
 }
 
 Output: (float())
 You need enum there, unfortunately. Also note the position of [], the lack of
traits import, the qualified import from std.stdio, the void return of main,
and so on.
 
 Bye,
 bearophile

Daniel Ribeiro Maciel <daniel.maciel gmail.com> writes:

The strange part is that, for some reason, this works:


import std.stdio: writeln;

class Foo {
    float bla() { return 0.0; }
    void foo() {}
}

void exportObject( TClass, members... )()
{
    foreach( uint i, member; members )
        writeln( typeid(typeof(__traits(getVirtualFunctions, Foo, members[i])
)) ); 
}

void main() {
    exportObject!( Foo, "bla", "foo" )();
}

Daniel Ribeiro Maciel Wrote:

 Heya!
 
 Ok, let me explain what I want to do:
 
 
  import std.stdio: writeln;
  
  class Foo {
      float bla() { return 0.0; }
      void foo() {}
  }
  
  void main() {
      enum string[] members = __traits(allMembers, Foo );
      foreach( member; members )
          writeln( typeid(typeof(__traits(getVirtualFunctions, Foo, member) ))
);
 }
 
 Is that possible?
 
 Best regards,
 Daniel
 
 
 bearophile Wrote:
 
 Daniel Ribeiro Maciel:
 
 Try this:
 
 import std.stdio: writeln;
 
 class Foo {
     float bla() { return 0.0; }
     void foo() {}
 }
 
 void main() {
     enum string[] members = ["bla", "foo"];
     writeln( typeid(typeof(__traits(getVirtualFunctions, Foo, members[0]) )) );
 }
 
 Output: (float())
 You need enum there, unfortunately. Also note the position of [], the lack of
traits import, the qualified import from std.stdio, the void return of main,
and so on.
 
 Bye,
 bearophile

 

bearophile <bearophileHUGS lycos.com> writes:

Daniel Ribeiro Maciel:

Note that this foreach is a static foreach because members is a tuple, it's not
an array:

 void exportObject( TClass, members... )()
 {
     foreach( uint i, member; members )
         writeln( typeid(typeof(__traits(getVirtualFunctions, Foo, members[i])
)) ); 
 }

I hope the the future real static foreach will work on enum (constant) arrays
too.

Bye,
bearophile

Trass3r <mrmocool gmx.de> writes:

Daniel Ribeiro Maciel schrieb:
  void main() {
      enum string[] members = __traits(allMembers, Foo );
      foreach( member; members )
          writeln( typeid(typeof(__traits(getVirtualFunctions, Foo, member) ))
);
 }
 
 Is that possible?
 

__traits is a really immature thing.

There's this bug that's been existing since ages:
http://d.puremagic.com/issues/show_bug.cgi?id=1386

I posted a strange workaround there. Don't know if it works for 
getVirtualFunctions as well though.