Type casting for user defined objects

Question

Just like we do with __ToString, is there a way to define a method for casting?

$obj = (MyClass) $another_class_obj;

Answer 1

I reworked the function Josh posted (which will error because of the undefined $new_class variable). Here's what I got:

function changeClass(&$obj, $newClass)
{   $obj = unserialize(preg_replace // change object into type $new_class
    (   "/^O:[0-9]+:\"[^\"]+\":/i", 
        "O:".strlen($newClass).":\"".$newClass."\":", 
        serialize($obj)
    ));
}

function classCast_callMethod(&$obj, $newClass, $methodName, $methodArgs=array())
{   $oldClass = get_class($obj);
    changeClass($obj, $newClass);

    // get result of method call
    $result = call_user_func_array(array($obj, $methodName), $methodArgs);
    changeClass(&$obj, $oldClass);  // change back
    return $result;
}

It works just like you'd expect a class cast to work. You could build something similar for accessing class members - but I don't think I would ever need that, so i'll leave it to someone else.

Boo to all the jerks that say "php doesn't cast" or "you don't need to cast in php". Bullhockey. Casting is an important part of object oriented life, and I wish I could find a better way to do it than ugly serialization hacks.

So thank you Josh!