Re: Self function

[Georg Wrede]

BCS wrote:
Reply to Georg,
bearophile wrote:

Sometimes I rename recursive functions, or I duplicate and modify

them, and they stop working because inside them there's one or more
copy of their old name, so for example they recurse to their old name.

So inside a function I'd like to have a standard name to call the

function itself, useful for recursivity.

(If you have two or more recursive functions that call each other
this

idea can't be used, but I think such situations are uncommon enough to
not deserve help from the language).

I have just discussed this in the Python newsgroup too:
http://groups.google.com/group/comp.lang.python/browse_thread/thread/
d265da85d4b70eaf#

I use more recursivity in D than in Python, because Python has
troubles with it.

In future in D2 you may use:

int ANUGLYNAME(int n) {
if (n <= 1)
return 1;
else
mixin(__FUNCTION__ ~ "(n - 1) * n");
}
But you can't use __FUNCTION__ into a delegate/function
pointer/lambdabecause the name isn't available, and it's a bit ugly
syntax anyway...

This looks a bit better:

int ANUGLYNAME(int n) {
if (n <= 1)
return 1;
else
__self(n - 1) * n;
}
Other syntaxes are possible.

__self is a way to denote the pointer/delegate of the function
currently being run, so I think the compiler is always able to that,
for
delegate/ function pointers/ lambdas/ methods/ virtual methods/
opCalls too.
Since you need this at compile time, then you don't need a pointer. A
name would be enough.

If, as Denis pointed out, Andrei is going to provide that, and if it
turns out to have a long name (like scope.function.name), then I hope
it will be implemented so that you can alias that into something
shorter, like "thisf" or "me".



void main()
{
  int i = 0;
  auto dg = (int j)
  {
      i++;
      return j <= 1 ? 1 : self(j-1) + self(j-2);
      // self can't be a name as the function dosn't have a name       
// and it can't be a compile time const at the context is not known.
  };

  dg(5);
}

Oh boy, I missed half of the post. (Note to self: remember use two eyes 
for reading. Especially at the wee hours.)