Parent object type hinting in PHP

Question

I'm trying to type hint for a specific parent object in PHP:

I've current got a standard base object class:

class stdObject
{

   private $var;

   public function setVar($var)
   {
     $this->var = $var;
     return $this;
   }
}

And I have a class object that extends this:

class valObject extends stdObject
{
}

In a PHP function, I want to be able to type hint so that the function can expect any object that has a parent of stdObject, so sending in valObject would work but not anyOldObject.

Is this possible?

Answer 1

You can by using the parent type :

function test(stdObject $obj) {
  // ...
}

If you don't want to have a pure stdObject as parameter, but only an object that inherit stdObject, you should put your stdObject class abstract or create an interface.

Answer 2

Is this possible?

Yes, what you've descrived is exactly what type hinting is for. Here is the documentation.