php merge class variables instead of replacing them - php

Question

i have multiple php classes
// a Base class
abstract class Base_Page {
protected static $config = array(
'status' => 'int',
);
}
// an inheriting class
class Page extends Base_Page{
protected static $config = array(
'title' => 'varchar',
'description' => 'text',
);
// and one more level of inheritance
class Page_Redirect extends Base_Page {
protected static $config = array(
'href' => 'http://domain.com',
);
}
now id'd like to do this:
$page_redirect = new Page_Redirect();
$page_redirect->getConfig(); // which i assume to be implemented (this is my problem)
// should return:
// array(
// 'status' => 'int',
// 'title' => 'varchar',
// 'description' => 'text',
// 'href' => 'http://domain.com',
// )
Due to the fact that the variable gets overwrote by the extending class a dont't get how to accomplish this. Thanks for your look at it.

Answer 1

You cannot do this with a bare property. It would be much better to use methods instead:
abstract class Base_Page {
protected function getConfig() {
return array('status' => 'int');
}
}
// an inheriting class
class Page extends Base_Page{
protected function getConfig() {
return array(
'title' => 'varchar',
'description' => 'text',
) + parent::getConfig();
}
}
// and one more level of inheritance
class Page_Redirect extends Base_Page {
protected function getConfig() {
return array(
'href' => 'http://domain.com',
) + parent::getConfig();
}
}
Of course now you have lost the ability to get the configuration statically, but it's highly likely that this does not matter. If it does (i.e. you need to know the configuration without having an instance at hand, and it is meaningless to create one on a whim) then the code needs further refactoring.

Answer 2

<?php
// a Base class
abstract class Base_Page {
protected static $config = array(
'status' => 'int',
);
}
// an inheriting class
class Page extends Base_Page {
protected static $config = array_merge(
parent::$config,
array(
'title' => 'varchar',
'description' => 'text',
)
);
}
Try something like this.