note 105564 added to functions.anonymous

Using closure to encapsulate environment <?php $fib = function($n) use(&$fib) { if($n == 0 || $n == 1) return 1; return $fib($n - 1) + $fib($n - 2); }; echo $fib(2) . "\n"; // 2 $lie = $fib; $fib = function(){die('error');};//rewrite $fib variable echo $lie(5); // error because $fib is referenced by closure ?> Alternative Fibonacci implementation using a self called function like javascript to encapsulate references variables. <?php $fib = call_user_func(function(){ $fib = function($n) use(&$fib) { if($n == 0 || $n == 1) return 1; return $fib($n - 1) + $fib($n - 2); }; return $fib; }); echo $fib(2) . "\n";//2 $ok = $fib; $fib = function(){die('error')};//rewrite $fib variable but don't referenced $fib used by closure echo $ok(5);//result ok ?> ---- Server IP: 69.147.83.197 Probable Submitter: 187.119.109.233 ---- Manual Page -- http://www.php.net/manual/en/functions.anonymous.php Edit -- https://master.php.net/note/edit/105564 Del: integrated -- https://master.php.net/note/delete/105564/integrated Del: useless -- https://master.php.net/note/delete/105564/useless Del: bad code -- https://master.php.net/note/delete/105564/bad+code Del: spam -- https://master.php.net/note/delete/105564/spam Del: non-english -- https://master.php.net/note/delete/105564/non-english Del: in docs -- https://master.php.net/note/delete/105564/in+docs Del: other reasons-- https://master.php.net/note/delete/105564 Reject -- https://master.php.net/note/reject/105564 Search -- https://master.php.net/manage/user-notes.php