Re: Callback function as parameter

* Francisco M. Marzoa Alonso <fmmarzoa@gmx.net>: > I want to wrote a function that receives another function as parameter > that will be used as a Callback. Well, better a bit of code than > thousand words: > > class TreeNode { > ... > function Traverse ( CallBack ) { > $rtn = CallBack ($this); > foreach ($this->Sons as $Son) { > $Son->Traverse ( CallBack ); > } > return $rtn; > } > ... > } > > And later I'll do something as: > > function CallBack ( $Node ) { > echo $Node->Name; > } > > $MyTreeNode->Traverse ( CallBack ); > > ... > > Hope you understand what I'm trying to do. Can it be done as is or am I > on the wrong way? Two ways to do it: 1) Pass a string that is the callback function's name; then call it a dynamic variable function: function Traverse($callback) { $rtn = $callback($this); ... } 2) Use a PHP callback pseudotype (http://php.net/pseudo-types): function Traverse($callback) { // Calls the callback with $this as its argument: $rtn = call_use_func($callback, $this); ... } Callbacks can be either a string containing a function name or an array with the first element either a class name or object reference and the second argument a method name (the first does a static method call, the second an object method call). -- Matthew Weier O'Phinney | mailto:matthew@garden.org Webmaster and IT Specialist | http://www.garden.org National Gardening Association | http://www.kidsgardening.com 802-863-5251 x156 | http://nationalgardenmonth.org