• Jason House (24/24) May 30 2007 I have a multi-threaded application where I pass delegates between
• Daniel Keep (16/43) May 30 2007 static void delegate() create(foo x, int param)
• Jason House (6/44) May 31 2007 ... or very similar. I think I mean to do

Jason House <jason.james.house gmail.com> writes:

I have a multi-threaded application where I pass delegates between 
threads.  While I thought this was a good design in the beginning, I 
find myself having to create a lot of helper objects...  Is there any 
way to avoid all the extra typing?  Any candidate additions to the 
language that'd help? :)

The following results in a run time error:
void example(){
   foreach(foo x; objectList)
     passDelegate({x.func(7);});
}

The following works but is annoying to keep typing:

class Helper{
   foo x;
   int param;
   this(foo _x, int _param){
     x     = _x;
     param = _param;
   }
   void opCall(){x.func(param);}
}
void example(){
   foreach(foo x; objectList)
     passDelegate(&(new Helper(x,7)).opCall);
}

Daniel Keep <daniel.keep.lists gmail.com> writes:

Jason House wrote:
 I have a multi-threaded application where I pass delegates between
 threads.  While I thought this was a good design in the beginning, I
 find myself having to create a lot of helper objects...  Is there any
 way to avoid all the extra typing?  Any candidate additions to the
 language that'd help? :)
 
 The following results in a run time error:
 void example(){
   foreach(foo x; objectList)
     passDelegate({x.func(7);});
 }
 
 The following works but is annoying to keep typing:
 
 class Helper{
   foo x;
   int param;
   this(foo _x, int _param){
     x     = _x;
     param = _param;
   }
   void opCall(){x.func(param);}

    static void delegate() create(foo x, int param)
    {
      return &(new Helper(x,param)).opCall;
    }
 }
 void example(){
   foreach(foo x; objectList)
     passDelegate(Helper.create(x,7));
 }

Like that?

	-- Daniel

-- 
int getRandomNumber()
{
    return 4; // chosen by fair dice roll.
              // guaranteed to be random.
}

http://xkcd.com/

v2sw5+8Yhw5ln4+5pr6OFPma8u6+7Lw4Tm6+7l6+7D
i28a2Xs3MSr2e4/6+7t4TNSMb6HTOp5en5g6RAHCP  http://hackerkey.com/

Jason House <jason.james.house gmail.com> writes:

Daniel Keep wrote:
 
 Jason House wrote:
 I have a multi-threaded application where I pass delegates between
 threads.  While I thought this was a good design in the beginning, I
 find myself having to create a lot of helper objects...  Is there any
 way to avoid all the extra typing?  Any candidate additions to the
 language that'd help? :)

 The following results in a run time error:
 void example(){
   foreach(foo x; objectList)
     passDelegate({x.func(7);});
 }

 The following works but is annoying to keep typing:

 class Helper{
   foo x;
   int param;
   this(foo _x, int _param){
     x     = _x;
     param = _param;
   }
   void opCall(){x.func(param);}

     static void delegate() create(foo x, int param)
     {
       return &(new Helper(x,param)).opCall;
     }
 }
 void example(){
   foreach(foo x; objectList)
     passDelegate(Helper.create(x,7));
 }

 
 Like that?
 
 	-- Daniel
 

... or very similar.  I think I mean to do
passDelegate( &(new Helper(x,7)).opCall );

I found std.bind which provides the functionality I was looking for. 
The .ptr() threw me for a loop, but I have it down now.

passDelegate( bind(&x.func,7).ptr() );