• Li Jie <cpunion gmail.com> Aug 13 2006
• Derek Parnell <derek psyc.ward> Aug 13 2006
• Kirk McDonald <kirklin.mcdonald gmail.com> Aug 13 2006
• BCS <BCS pathlink.com> Aug 14 2006

Li Jie <cpunion gmail.com> writes:

class Test{
  void a(int n){}
}

auto a = &Test.a;
auto t = new Test;
a(t, 1); // or: a.bind(t); a(1);

Is this supported?

Derek Parnell <derek psyc.ward> writes:

On Sun, 13 Aug 2006 20:32:25 +0000 (UTC), Li Jie wrote:

 class Test{
   void a(int n){}
 }
 
 auto a = &Test.a;
 auto t = new Test;
 a(t, 1); // or: a.bind(t); a(1);
 
 Is this supported?


I do not know what 'bind' means in this context. Is it a Java term? Why is
it needed?

-- 
Derek Parnell
Melbourne, Australia
"Down with mediocrity!"

Kirk McDonald <kirklin.mcdonald gmail.com> writes:

Li Jie wrote:
 class Test{
   void a(int n){}
 }
 
 auto a = &Test.a;
 auto t = new Test;
 a(t, 1); // or: a.bind(t); a(1);
 
 Is this supported?


You want pointers to member functions, as C++ has. D does not have 
these. Rather, it has delegates, which are often more useful:

class Test {
     void a (int n) {}
}

Test t = new Test;
void delegate(int) dg = &t.a;
dg(1);

This use of delegates is documented here:
http://www.digitalmars.com/d/function.html#closures

If you're looking for pointers to member functions to implement some 
sort of dispatch mechanism, delegates do not directly allow this. 
However, there do exist hacks to allow it.

-- 
Kirk McDonald
Pyd: Wrapping Python with D
http://dsource.org/projects/pyd/wiki

BCS <BCS pathlink.com> writes:

Li Jie wrote:
 class Test{
   void a(int n){}
 }
 
 auto a = &Test.a;
 auto t = new Test;
 a(t, 1); // or: a.bind(t); a(1);
 
 Is this supported?



something like this works

#	// inline function
#auto b = function(Test t)
#	{
#		t.a;
#	}
#
#auto t = new Test;
#
#	// call function
#b(t);

Add parameters to the function if a has parameters.

Also say Test has a "real c(char[],int,int)" and you don't want to set 
all of it's parameters, you can do this:

#int i,j;
#
#auto d = (Test test, char[] ch)
#	{
#		// take ch as arg
#		// pull i,j from context
#		return test.c(ch,i,j);
#	}
#
#	// only need one peram here
#auto ret = d(t,"foo");