abstract class Base
{
abstract function foo();
}

class DerivedA extends Base
{
function foo() { print “In A foo()\n”; }
}

class DerivedB extends Base
{
function foo() { print “In B foo()\n”; }
}

function do_foo( $obj )
{
if( ! is_subclass_of( $obj, ‘Base’ ) )
{
throw new Something();
}
$obj->foo();
}

Sure, you could ignore the fact that you’re supposed to use the interface in this case, and use the object’s other methods, but that’s just you being ignorant.

Yes, it has support for objects. Yes, it has support for PPP access, but it doesn’t have casting:

$b = new Foo();
$a = (Foo)$b;

Casting to a specific object class generates a syntax error. This completely removes the OOP tenant of “polymorphism” off the table. It also makes Interfaces a waste of time in PHP. These aren’t necessarily bad things if you consider PHP to be it’s own unique language. But if you’re going to jump on the OOP bandwagon, at least get all the way on it.

Still, in the 4 branch, objects without defined member variables equal null (but they don’t === null). I point this out because it should never have happened in a language where objects are “first class citizens”.

I won’t go into the problems with mixing static and non-static contexts.

It seems to me that if you don’t think about objects the same way that the developers of PHP do (and it doesn’t appear that they think about OOP even close to any other modern language), you are SOL.

php -r ‘var_dump((object)1 instanceof stdClass);’

What’s even weirder is that the follow is true