Are subclasses allowed?

tony_l

Just a quick question that hit me just a minute ago.... Does PHP allow for subclasses? If so, I am assuming you create the subclass within the main class, or does php have a different syntax for it? The manual does not mention subclasses that I could find.

robert_w_ark

I don't think you can. Then again, I don't use 'subclasses' so maybe you could just try it 🙂

class Parent_Class
{
  class Child_Class
  {
    function cclass_func1()
    {
      echo "Child Class - Function 1";
    }

function cclass_func2()
{
  echo "Child Class - Function 2";
}
  }

  function pclass_func1()
  {
    echo "Parent Class - Function 1";
  }

  function pclass_func2()
  {
    echo "Parent Class - Function 2";
  }
}

$myClass = new ParentClass;

Then again, I don't know how you would use the child classes if you can't declare it =\

Don't know 🙁

thorpe

it does have inheritence if thats what you meen. well, php5 does.

tony_l

Well the parent class would declare the subclass. I just did about two hours of testing, and you know what? it actually works! .... sorta. I need to figure out the kinks a bit more. It obviously has some behaviors I am not used to.

Inheritance is where you extend a class. I was actually talking about a class that contains another class that is defined that class. Like a class called Car may have a subclass called Steering Wheel. Steering Wheel would not be able to be implemented by any other class (or even called) by anything other than Car.

Weedpacket

PHP doesn't have a syntax for inner classes. What I typically consider doing is something like

class Car{}
class Car_SteeringWheel{}

tagging the wannabe inner class with the name of its "outer class".

And then have them in the same file, and have the user documentation describing only Car.
Oh, I usually find that Car_SteeringWheel's constructor can do with a parameter to indicate which Car is instantiating it. So that a Car creates a SteeringWheel as

$this->steering_wheel = new Car_SteeringWheel($this);

and then Car_SteeringWheel's contructor starts

function __construct($car)
{
  $this->car = $car;
...
}

Because usually the inner object wants access to the outer object's properties (The constructor, note, implies PHP5 - I tended not to use OO in such fancy ways in PHP4).

Anyway, that's want I'm considering at present. Things like access control still need ironing out, of course.