How do I get a PHP class constructor to call its parent's parent's constructor?

Question

I need to have a class constructor in PHP call its parent\'s parent\'s (grandparent?) constructor without calling the parent constructor.

//         


        

Answer 1

I agree with "too much php", try this:

class Grandpa 
{
    public function __construct()
    {
        echo 'Grandpa
';
    }

}

class Papa extends Grandpa
{
    public function __construct()
    {
        echo 'Papa
';
        parent::__construct();
    }
}

class Kiddo extends Papa
{
    public function __construct()
    {
        // THIS IS WHERE I NEED TO CALL GRANDPA'S
        // CONSTRUCTOR AND NOT PAPA'S
        echo 'Kiddo
';
        Grandpa::__construct();
    }
}

$instance = new Kiddo;

I got the result as expected:

Kiddo

Grandpa

This is a feature not a bug, check this for your reference:

https://bugs.php.net/bug.php?id=42016

It is just the way it works. If it sees it is coming from the right context this call version does not enforce a static call.

Instead it will simply keep $this and be happy with it.

parent::method() works in the same way, you don't have to define the method as static but it can be called in the same context. Try this out for more interesting:

class Grandpa 
{
    public function __construct()
    {
        echo 'Grandpa
';
        Kiddo::hello();
    }

}

class Papa extends Grandpa
{
    public function __construct()
    {
        echo 'Papa
';
        parent::__construct();
    }
}

class Kiddo extends Papa
{
    public function __construct()
    {
        // THIS IS WHERE I NEED TO CALL GRANDPA'S
        // CONSTRUCTOR AND NOT PAPA'S
        echo 'Kiddo
';
        Grandpa::__construct();
    }

    public function hello()
    {
        echo 'Hello
';
    }
}

$instance = new Kiddo;

It also works as expected:

Kiddo

Grandpa

Hello

But if you try to initialize a new Papa, you will get an E_STRICT error:

$papa = new Papa;

Strict standards: Non-static method Kiddo::hello() should not be called statically, assuming $this from incompatible context

You can use instanceof to determine if you can call a Children::method() in a parent method:

if ($this instanceof Kiddo) Kiddo::hello();