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# XCVII. Object property and method call overloading

# Introduktion

The purpose of this extension is to allow overloading of object property access and method calls. Only one function is defined in this extension, overload() which takes the name of the class that should have this functionality enabled. The class named has to define appropriate methods if it wants to have this functionality: __get(), __set() and __call() respectively for getting/setting a property, or calling a method. This way overloading can be selective. Inside these handler functions the overloading is disabled so you can access object properties normally.

Advarsel
Denne udvidelse er EKSPERIMENTABEL. Virkemåden af denne udvidelse -- inklusiv navnene på des funktioner og alt andet dokumenteret om udvidelsen -- ændres muligvis uden advarsel, i en fremtidig version af PHP. Brug af denne udvidelse er på ejet ansvar.

Advarsel
This extension is not a part of PHP 5. PHP 5 supports __get(), __set() and __call() natively. See the Overloading in PHP 5 page for more information.

# Systemkrav

Ingen eksterne libraries er nødvendige for at kompilere denne udvidelse.

# Installation

In order to use these functions, you must compile PHP with the --enable-overload option. Starting with PHP 4.3.0 this extension is enabled by default. You can disable overload support with --disable--overload.

Windows versionen af PHP har indbygget support for denne udvidelse. Du behøver ikke indsætte ekstra udvidelser for at bruge disse funktioner.

> Bemærk: Builtin support for overload is available with PHP 4.3.0.

# Runtime Konfiguration

Denne udvidelse har intet konfigurations-direktiv defineret i `php.ini`.

# Ressourcetyper

Denne udvidelse har ingen ressourcetyper defineret.

# Foruddefinerede Konstanter

Denne udvidelse har ingen konstanter.

# Eksempler

Some simple examples on using the overload() function:

Eksempel 1. Overloading a PHP class

`<?php
class OO {
var $a = 111;
var $elem = array('b' => 9, 'c' => 42);
// Callback method for getting a property
function __get($prop_name, &$prop_value)
{
if (isset($this->elem[$prop_name])) {
$prop_value = $this->elem[$prop_name];
return true;
} else {
return false;
}
}
// Callback method for setting a property
function __set($prop_name, $prop_value)
{
$this->elem[$prop_name] = $prop_value;
return true;
}
}
// Here we overload the OO object
overload('OO');
$o = new OO;
echo "\$o->a: $o->a\n"; // print: $o->a: 111
echo "\$o->b: $o->b\n"; // print: $o->b: 9
echo "\$o->c: $o->c\n"; // print: $o->c: 42
echo "\$o->d: $o->d\n"; // print: $o->d:
// add a new item to the $elem array in OO
$o->x = 56;
// instantiate stdclass (it is built-in in PHP 4)
// $val is not overloaded!
$val = new stdclass;
$val->prop = 555;
// Set "a" to be an array with the $val object in it
// But __set() will put this in the $elem array
$o->a = array($val);
var_dump($o->a[0]->prop);
?>`

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