Still trying to figure out oop in PHP5. The question is, how to access a parent's static variable from an extended class' method. Example below.
<?php
error_reporting(E_ALL);
class config {
public static $base_url = 'http://example.moo';
}
class dostuff extends config {
public static function get_url(){
echo $base_url;
}
}
dostuff::get_url();
?>
I thought this would work from experience in other languages.
It's completely irrelevant that the property is declared in the parent, you access it the way you access any static property:
self::$base_url
or
static::$base_url // for late static binding
Another doing Parent::Prop (this doesn't work, but is there a way, doing some kind of late-static-binding-polymorphism)?
Yes, it's possible, but actually should be written like this:
class dostuff extends config {
public static function get_url(){
echo parent::$base_url;
}
}
But in this case you can access it both with self::$base_url and static::$base_url - as you don't redeclare this property in the extending class. Have you done it so, there would have been a distinction:
self::$base_url would always refer to the property in the same class that line's written, static::$base_url to the property of the class the object belongs to (so called 'late static binding').Consider this example:
class config {
public static $base_url = 'http://config.example.com';
public function get_self_url() {
return self::$base_url;
}
public function get_static_url() {
return static::$base_url;
}
}
class dostuff extends config {
public static $base_url = 'http://dostuff.example.com';
}
$a = new config();
echo $a->get_self_url(), PHP_EOL;
echo $a->get_static_url(), PHP_EOL; // both config.example.com
$b = new dostuff();
echo $b->get_self_url(), PHP_EOL; // config.example.com
echo $b->get_static_url(), PHP_EOL; // dostuff.example.com
