• Vova (7/7) Mar 30 2005 Hello All !
• Chris Sauls (18/27) Mar 30 2005 I believe its because delegates contain a referance to the class
• Vladimir (23/53) Mar 30 2005 argument, but I want to pass
• Carlos Santander B. (6/31) Mar 30 2005 Say you're doing this inside a class non-static member function. Which
• Russ Lewis (10/35) Mar 30 2005 Well, if you're casting a function pointer to a delegate, then it

Vova <Vova_member pathlink.com> writes:

Hello All ! 
I have function that accepts delegate as it's argument, but I want to pass 
ordinary function to it. Of couse I can create class which encapsulates that 
function, but it seems to be an ugly hack (that was good in C++). 
I'm wondering why 
cast(delegate int(int)) myfunc 
does not work. 

Chris Sauls <ibisbasenji gmail.com> writes:

Vova wrote:
 Hello All ! 
 I have function that accepts delegate as it's argument, but I want to pass 
 ordinary function to it. Of couse I can create class which encapsulates that 
 function, but it seems to be an ugly hack (that was good in C++). 
 I'm wondering why 
 cast(delegate int(int)) myfunc 
 does not work. 
 
 

I believe its because delegates contain a referance to the class 
instance or stack frame where they are born.  Casting a function to a 
delegate would leave one with a null referance, and that is apparently a 
"bad thing".  I do believe Walter intends to unify functions and 
delegates in the future though, probably by just allowing the null 
referance and making a special case of it, or some such.  Meanwhile, 
might a delegate literal be a more acceptable hack?  Something like:











-- Chris Sauls

Vladimir <Vladimir_member pathlink.com> writes:

In article <d2eidl$1eev$1 digitaldaemon.com>, Chris Sauls says... 
 
Vova

wrote: 
 Hello All !  
 I have function that accepts delegate as it's


argument, but I want to pass  
 ordinary function to it. Of couse I can create


class which encapsulates that  
 function, but it seems to be an ugly hack


(that was good in C++).  
 I'm wondering why  
 cast(delegate int(int))


myfunc  
 does not work.  
  
  

 
I believe its because delegates

contain a referance to the class  
instance or stack frame where they are born.

But what happens with delegate when it's stack frame is destroyed ? 
 

Casting a function to a  
delegate would leave one with a null referance, and

that is apparently a  
"bad thing".  I do believe Walter intends to unify

functions and  
delegates in the future though, probably by just allowing the

null  
referance and making a special case of it, or some such.  

I really do
believe in it too. 
 
 Meanwhile,  
might a delegate literal be a more

acceptable hack?  Something like: 
 




something (int delegate(int) dg) { ... } 




(int a) { 




Yes, it look quite good.
Thanks a lot. 
But why not to make casting function to delegate to do the same
thing ? 

"Carlos Santander B." <csantander619 gmail.com> writes:

Vladimir wrote:
 
 acceptable hack?  Something like: 
 




 
 something (int delegate(int) dg) { ... } 
 




 
 (int a) { 
 




 
 Yes, it look quite good.
 Thanks a lot. 
 But why not to make casting function to delegate to do the same
 thing ? 
 
 

Say you're doing this inside a class non-static member function. Which 
frame should be passed: the current function or the current object? 
That's the only problem I can see right now.

_______________________
Carlos Santander Bernal

Russ Lewis <spamhole-2001-07-16 deming-os.org> writes:

Carlos Santander B. wrote:
 Vladimir wrote:
 
 acceptable hack?  Something like:




 something (int delegate(int) dg) { ... }




 (int a) {



 Yes, it look quite good.
 Thanks a lot. But why not to make casting function to delegate to do 
 the same
 thing ?

 
 Say you're doing this inside a class non-static member function. Which 
 frame should be passed: the current function or the current object? 
 That's the only problem I can see right now.

Well, if you're casting a function pointer to a delegate, then it 
doesn't matter.  Remember, if you have a function pointer to a class 
member, then it must be a static class member, and so there isn't any 
'current object' that would apply to it.

While we're on the subject, I'll note that it is currently not possible 
to declare a delegate literal where the object pointer is anything other 
than the stack frame.  I've proposed a syntax to Walter where you could 
pass an object (or struct) pointer as the the pointer, but he doesn't 
seem to be interested in it, at least not yet.