Accept function as parameter in PHP

Question

I\'ve been wondering whether is possible or not to pass a function as parameter in PHP; I want something like when you\'re programming in JS:

object.exampleM         


        

Answer 1

Tested for PHP 5.3

As i see here, Anonymous Function could help you: http://php.net/manual/en/functions.anonymous.php

What you'll probably need and it's not said before it's how to pass a function without wrapping it inside a on-the-fly-created function. As you'll see later, you'll need to pass the function's name written in a string as a parameter, check its "callability" and then call it.

The function to do check:

if( is_callable( $string_function_name ) ){
    /*perform the call*/
}

Then, to call it, use this piece of code (if you need parameters also, put them on an array), seen at : http://php.net/manual/en/function.call-user-func.php

call_user_func_array( "string_holding_the_name_of_your_function", $arrayOfParameters );

as it follows (in a similar, parameterless, way):

    function funToBeCalled(){
        print("----------------------i'm here");
    }
    function wrapCaller($fun){
        if( is_callable($fun)){
            print("called");
            call_user_func($fun);
        }else{
            print($fun." not called");
        }
    }

    wrapCaller("funToBeCalled");
    wrapCaller("cannot call me");

Here's a class explaining how to do something similar :

functions[$name] = $data;
        else
            $this->vars[$name] = $data;
    }

    function __get($name){
        $t = $this->vars[$name];
        if(isset($t))
            return $t;
        else{
            $t = $this->$functions[$name];
            if( isset($t))
                return $t;
        }
    }

    function __call($method,$args=null){
        $fun = $this->functions[$method];
        if(isset($fun)){
            call_user_func_array($fun,$args);
        } else {
            // error out
            print("ERROR: Funciton not found: ". $method);
        }
    }
}
?>

and an example of usage

         
hello to 

    justPrintSomething = 'sayHello'; /*note that the given
        "sayHello" it's a string ! */

    /*now call it*/
    $obj->justPrintSomething(); /*will print: "hello to all" and
        a break-line, for html purpose*/

    /*if the string assigned is not denoting a defined method
         , it's treat as a simple value*/
    $obj->justPrintSomething = 'thisFunctionJustNotExistsLOL';

    echo $obj->justPrintSomething; /*what do you expect to print?
        just that string*/
    /*N.B.: "justPrintSomething" is treated as a variable now!
        as the __set 's override specify"*/

    /*after the assignement, the what is the function's destiny assigned before ? It still works, because it's held on a different array*/
     $obj->justPrintSomething("Jack Sparrow");


     /*You can use that "variable", ie "justPrintSomething", in both ways !! so you can call "justPrintSomething" passing itself as a parameter*/

     $obj->justPrintSomething( $obj->justPrintSomething );
         /*prints: "hello to thisFunctionJustNotExistsLOL" and a break-line*/

    /*in fact, "justPrintSomething" it's a name used to identify both
         a value (into the dictionary of values) or a function-name
         (into the dictionary of functions)*/
?>