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# XCII. Object property and method call overloading

# Introduction

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.

Varoitus
Varoitus! T�m� laajennus on EKSPERIMENTAALINEN. T�m�n laajennuksen ominaisuudet, k�ytt�ytyminen sek� funktioiden nimet ja parametrit voivat muuttua varoituksetta seuraavissa PHP:n versioissa.

Varoitus
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.

# Requirements

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# 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.

The windows version of PHP has built in support for this extension. You do not need to load any additional extension in order to use these functions.

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

# Runtime Configuration

T�m� laajennus ei m��rittele yht�k��n direktiivi� `php.ini`ss�.

# Resource Types

T�m� laajennus ei m��rittele yht�k��n resurssityyppi�.

# Predefined Constants

T�m� laajennus ei m��rittele yht�k��n uutta vakiota.

# Examples

Some simple examples on using the overload() function:

Esimerkki 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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