PHP passing a variable to array_walk_recursive

Question

This code works but $vars can't be defined in the call() function. Why do $vars can't be passed to the array_walk_recursive()?

class lib{

    private $library;

    function __construct($lib="")
    {
        $this->library = $lib;
    }
    function set($vars)
    {
        $decoded_classes = json_decode($this->library,true);
        array_walk_recursive($decoded_classes,function(&$f) {$f = create_function($vars,$f);});
        return $decoded_classes;
    }
}
$json = '
{     
    "class1": {     
        "function1":"return \"$a<b>$b</b>!\";"
    },
    "class2": {     
        "function2":"return $b;",
        "function3":"return $c;"
    },
    "function1":"return \"test\";"
}';
$lib = new lib($json);
$lib = $lib->set("$a,$b");
$lib = $lib["class1"]["function1"]("asdasasd","asdasasd");
echo $lib;

Answer 1

Firstly, have a look at this example with variable scoping for closures. You need to pass the variable in with the use keyword, eg:

array_walk_recursive($decoded_classes,function(&$f) use ($vars) {$f = create_function($vars,$f);});

It would be good if you defined $a, $b, etc for us, so we could actually test your code.