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

Although there's no need to type cast in PHP, you might come across a situation where you would like to convert a parent object into a child object.

Simple

//Example of a sub class
class YourObject extends MyObject {
    public function __construct(MyObject $object) {
        foreach($object as $property => $value) {
            $this->$property = $value;
        }
    }
}


$my_object = new MyObject();
$your_object = new YourObject($my_object);

So all you do is pass the parent object down to the child object's constructor, and let the constructor copy over the properties. You can even filter / change them as needed.

Advanced

//Class to return standard objects
class Factory {
    public static function getObject() {
        $object = new MyObject();
        return $object;
    }
}

//Class to return different object depending on the type property
class SubFactory extends Factory {
    public static function getObject() {
        $object = parent::getObject();
        switch($object->type) {
        case 'yours':
            $object = new YourObject($object);
            break;
        case 'ours':
            $object = new OurObject($object);
            break;
        }
        return $object;
    }
}

//Example of a sub class
class YourObject extends MyObject {
    public function __construct(MyObject $object) {
        foreach($object as $property => $value) {
            $this->$property = $value;
        }
    }
}

It's not type casting, but it does what you need.