简介

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.

需求

要编译本扩展模块不需要外部库文件。

安装

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.

PHP 的 Windows 版本已经内置该扩展模块的支持。无需加载任何附加扩展库即可使用这些函数。

运行时配置

本扩展模块在 php.ini 中未定义任何配置选项。

资源类型

本扩展模块未定义任何资源类型。

预定义常量

本扩展模块未定义任何常量。

范例

Some simple examples on using the overload() function:

例子 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); ?>