class Person {
    private $name;

    public function __construct($name) {
        $this->name = $name;
    }

    public function getName() {
        return $this->name;
    }

    public function getTitle() {
        return $this->getName()." the person";
    }

    public function sayHello() {
        echo "Hello, I'm ".$this->getTitle()."<br/>";
    }

    public function sayGoodbye() {
        echo "Goodbye from ".self::getTitle()."<br/>";
    }
}

class Geek extends Person {
    public function __construct($name) {
        parent::__construct($name);
    }

    public function getTitle() {
        return $this->getName()." the geek";
    }
}

This will output:


Hello, I'm Ludwig the geek
Goodbye from Ludwig the person


sayHello() uses the $this pointer, so the vtable is invoked to call Geek::getTitle(). sayGoodbye() uses self::getTitle(), so the vtable is not used, and Person::getTitle() is called. In both cases, we are dealing with the method of an instantiated object, and have access to the $this pointer within the called functions.