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Date: Sat, 11 Apr 2009 21:51:00 -0500
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Subject: Closures and __FUNCTION__
From: pcd@roxygen.org (Peter Danenberg)

The original anonymous functions patch[1] contained support for
__FUNCTION__ as a recursion mechanism in closures, such that I should
be able to do something like this:

  $factorial = function($n) {
      if ($n == 1)
        return 1;
      else
        return $n * call_user_func(__FUNCTION__, $n - 1);                                                                                                          
    };

  print $factorial(3);                  // => 6                                                                                                          

It fails with a warning, though:

  Warning: call_user_func() expects parameter 1 to be a valid
  callback, function '{closure}' not found or invalid function name

Is there another recursion mechanism for closures besides something
like the $GLOBALS['factorial'] hack?

Footnotes: 
[1]  http://marc.info/?l=php-internals&m=119995982228453&w=2