• Li Jie (7/7) Aug 13 2006 class Test{
• Derek Parnell (7/16) Aug 13 2006 I do not know what 'bind' means in this context. Is it a Java term? Why ...
• Kirk McDonald (18/27) Aug 13 2006 You want pointers to member functions, as C++ has. D does not have
• Li Jie (4/4) Aug 13 2006 If you're looking for pointers to member functions to implement...
• Kirk McDonald (16/21) Aug 14 2006 My own Pyd library requires this functionality to implement its class
• BCS (26/35) Aug 14 2006 something like this works

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

Li Jie <cpunion gmail.com> writes:

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

Thanks.
Delegate is very cool, but it bind too early.

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

Li Jie wrote:
 If you're looking for pointers to member functions to implement some
 sort of dispatch mechanism, delegates do not directly allow this.

 
 Thanks.
 Delegate is very cool, but it bind too early.

My own Pyd library requires this functionality to implement its class 
wrapping. I do not endorse this practice, but the dirty hack it uses to 
get the functionality is found here:

http://dsource.org/projects/pyd/browser/trunk/infrastructure/pyd/dg_convert.d

In essense, it constructs a delegate from an Object instance and a 
regular function pointer. It takes advantage of how delegates are 
represented internally, but this behavior is not guaranteed by the spec. 
It is therefore firmly in the realm of "dirty hacks."

Note that this module requires the ftype module originally written by 
Daniel Keep. The version of ftype in Pyd is slightly modified from his 
original.

-- 
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


#auto b = function(Test t)




#auto t = new Test;


#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)







#auto ret = d(t,"foo");