PHP: Calling Parent Class Constructors

For the past few weeks I have been working with PHP for a web application. With tons of annoyances, PHP can throw someone off balance if they are familiar with other languages.

One issue I came across, with tons of erroneous information regarding a solution, was a very simple issue of calling a parent classes constructor. For the below, I was using PHP 5.1.2 since I have been developing with PHPEclipse.

In this example, I have a base class, similar to this:

class BaseClass

{

private $_myValue;

function __construct()

{

$this->_myValue = new SomeClass();

}

}

Very simple, so I need this called in my extended class in order to initialize that myValue variable.

Now I saw some annoying solutions, which did not work, such as the below:

class DerivedClass extends BaseClass

{

private $_someOtherValuesNotInBase;

function __construct($initalizing)

{

$_ someOtherValuesNotInBase = $initalizing;

$this->BaseClass();

}

}

This didn’t work. PHP cried about not being able to find the method BaseClass(). Then I came across this little gem, which also did not work.

class DerivedClass extends BaseClass

{

private $_someOtherValuesNotInBase;

function __construct($initalizing)

{

$_ someOtherValuesNotInBase = $initalizing;

parent::BaseClass();

}

}

So, with all these erroneous solution, what is the correct answer? The following worked for me after some trial and error:

Class DerivedClass extends BaseClass

{

Private $_someOtherValuesNotInBase;

Function __construct($initalizing)

{

$_ someOtherValuesNotInBase = $initalizing;

$this->__construct();

}

}