How to add a new method to a php object on the fly?

Question

How do I add a new method to an object \"on the fly\"?

$me= new stdClass;
$me->doSomething=function ()
 {
    echo \'I\\\'ve done something\';
 };
$me->         


        

Answer 1

Using simply __call in order to allow adding new methods at runtime has the major drawback that those methods cannot use the $this instance reference. Everything work great, till the added methods don't use $this in the code.

class AnObj extends stdClass
{
    public function __call($closure, $args)
    {
        return call_user_func_array($this->{$closure}, $args);
    }
 }
 $a=new AnObj();
 $a->color = "red";
 $a->sayhello = function(){ echo "hello!";};
 $a->printmycolor = function(){ echo $this->color;};
 $a->sayhello();//output: "hello!"
 $a->printmycolor();//ERROR: Undefined variable $this

In order to solve this problem you can rewrite the pattern in this way

class AnObj extends stdClass
{
    public function __call($closure, $args)
    {
        return call_user_func_array($this->{$closure}->bindTo($this),$args);
    }

    public function __toString()
    {
        return call_user_func($this->{"__toString"}->bindTo($this));
    }
}

In this way you can add new methods that can use the instance reference

$a=new AnObj();
$a->color="red";
$a->sayhello = function(){ echo "hello!";};
$a->printmycolor = function(){ echo $this->color;};
$a->sayhello();//output: "hello!"
$a->printmycolor();//output: "red"