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digitalmars.D.learn - toDelegate() for D1

reply %u <e ee.com> writes:
is it available?
Jan 12 2011
parent reply %u <e ee.com> writes:
I only need something to make a void deleg() from a void func().
Jan 12 2011
parent reply "Simen kjaeraas" <simen.kjaras gmail.com> writes:
%u <e ee.com> wrote:


 I only need something to make a void deleg() from a void func().


This works for me:

ReturnType!( F ) delegate( ParameterTypeTuple!( F ) ) toDelegate( F )( F  
fn ) {
     return ( ParameterTypeTuple!( F ) args ){ return fn( args ); };
}

-- 
Simen
Jan 12 2011
next sibling parent %u <e ee.com> writes:
== Quote from Simen kjaeraas (simen.kjaras gmail.com)'s article

 %u <e ee.com> wrote:

 I only need something to make a void deleg() from a void func().


 This works for me:
 ReturnType!( F ) delegate( ParameterTypeTuple!( F ) ) toDelegate( F )( F
 fn ) {
      return ( ParameterTypeTuple!( F ) args ){ return fn( args ); };
 }


I see what you did there(took me a few blinks and spec lookups): function
literals
default to delegates :)
Thanks!!
Jan 12 2011
prev sibling parent reply %u <e ee.com> writes:
== Quote from Simen kjaeraas (simen.kjaras gmail.com)'s article

 %u <e ee.com> wrote:

 I only need something to make a void deleg() from a void func().


 This works for me:
 ReturnType!( F ) delegate( ParameterTypeTuple!( F ) ) toDelegate( F )( F
 fn ) {
      return ( ParameterTypeTuple!( F ) args ){ return fn( args ); };
 }


What am I doing wrong. I can't call the delegate twice with anything in between.

----
void func(){ writefln("func"); }

void main(){
  void delegate() dg;
  dg = toDelegate(&func);
  dg(); // np
  //writefln(dg.ptr," ", dg.funcptr,"."); // Error: Stack Overflow   second dg
call
  //writefln(); // Error: Access Violation   second dg call
  dg();
}
----
Jan 13 2011
next sibling parent reply Moritz Warning <moritzwarning web.de> writes:
On Thu, 13 Jan 2011 17:14:13 +0000, %u wrote:


 == Quote from Simen kjaeraas (simen.kjaras gmail.com)'s article

 %u <e ee.com> wrote:

 I only need something to make a void deleg() from a void func().


 This works for me:
 ReturnType!( F ) delegate( ParameterTypeTuple!( F ) ) toDelegate( F )(
 F fn ) {
      return ( ParameterTypeTuple!( F ) args ){ return fn( args ); };
 }


 
 What am I doing wrong. I can't call the delegate twice with anything in
 between.
 
 ----
 void func(){ writefln("func"); }
 
 void main(){
   void delegate() dg;
   dg = toDelegate(&func);
   dg(); // np
   //writefln(dg.ptr," ", dg.funcptr,"."); // Error: Stack Overflow  
   second dg call //writefln(); // Error: Access Violation   second dg
   call dg();
 }
 ----


My tangofied of this code works, maybe it's a lib bug?
On the other hand, is the delegate allocated on the stack?
Anyway, here is another way:

R delegate(T) toDg(R, T...)(R function(T) fp)
{
    struct dg
    {
        R opCall(T t)
        {
            return (cast(R function(T)) this) (t);
        }
    }
    
    R delegate(T) t;
    t.ptr = fp;
    t.funcptr = &dg.opCall;
    return t;
}
Jan 13 2011
parent "Simen kjaeraas" <simen.kjaras gmail.com> writes:
Moritz Warning <moritzwarning web.de> wrote:


 My tangofied of this code works, maybe it's a lib bug?
 On the other hand, is the delegate allocated on the stack?
 Anyway, here is another way:

 R delegate(T) toDg(R, T...)(R function(T) fp)
 {
     struct dg
     {
         R opCall(T t)
         {
             return (cast(R function(T)) this) (t);
         }
     }
    R delegate(T) t;
     t.ptr = fp;
     t.funcptr = &dg.opCall;
     return t;
 }


Man, that's almost as ugly as some of the things I do. :p
That's plenty fine if it works, though.

-- 
Simen
Jan 14 2011
prev sibling parent Stewart Gordon <smjg_1998 yahoo.com> writes:
On 13/01/2011 17:14, %u wrote:

 == Quote from Simen kjaeraas (simen.kjaras gmail.com)'s article

 %u<e ee.com>  wrote:

 I only need something to make a void deleg() from a void func().


 This works for me:
 ReturnType!( F ) delegate( ParameterTypeTuple!( F ) ) toDelegate( F )( F
 fn ) {
       return ( ParameterTypeTuple!( F ) args ){ return fn( args ); };
 }


 What am I doing wrong. I can't call the delegate twice with anything in
between.


Every delegate needs a context pointer.  If the function is defined 
within a function, that context pointer points to the stack frame of the 
function that defined it.  And in this case it uses something from that 
very stack frame: the parameter fn.

ISTM it works straight after you've created it only because the stack 
frame of toDelegate has not yet been overwritten.  However, I'm still 
puzzled, because the process of calling the delegate ought to itself 
overwrite the stack frame.

You want this:

http://pr.stewartsplace.org.uk/d/sutil/

Stewart.
Jan 14 2011