Delegate returning itself

[Jonathan Marler via Digitalmars-d-learn]

On Monday, 8 December 2014 at 14:08:33 UTC, Jonathan Marler wrote:
> On Saturday, 6 December 2014 at 15:46:16 UTC, Adam D. Ruppe 
> wrote:
>> The problem is the recursive *alias* rather than the delegate. 
>> Just don't use the alias name inside itself so like
>>
>> alias MyDelegate = void delegate() delegate();
>>
>> will work. The first void delegate() is the return value of 
>> the MyDelegate type.
>
> Yes I tried that as well.  It still doesn't solve the issue.  
> The delegate being returned doesn't return a delegate, it 
> returns the "void" type.  You would need to write delegate() 
> delegate() delegate() delegate() ...FOREVER.  I can't figure 
> out a way to write this in the language even though the machine 
> code it generates should be quite trivial.

I did some digging and realized that C/C++ have the same problem. 
  I found a nice post on it with 2 potential solutions 
(http://c-faq.com/decl/recurfuncp.html).  I liked the second 
solution so I wrote up an example in D.  If anyone has any other 
ideas or can think of a way to improve my example feel free to 
post and let me know, thanks.import std.stdio;

struct StateFunc
{
   StateFunc function() func;
}
StateFunc state1()
{
   writeln("state1");
   return StateFunc(&state2);
}
StateFunc state2()
{
   writeln("state2");
   return StateFunc(&state3);
}
StateFunc state3()
{
   writeln("state3");
   return StateFunc(null);
}
void main(string[] args)
{
   StateFunc state = StateFunc(&state1);

   while(state.func != null) {
     state = state.func();
   }
}