PHP 以类作为值提取数组

Question

我正在开发一个 MVC 框架，但我在声明帮助类时遇到了一个灵活的代码/结构的问题

class Controller {
    public $helper = [];

    public function load_helper($helper)    {
        require_once(DIR_HELPER . $helper . '.php');
        $lc_helper = StrToLower($helper);
        $helper_arr[$lc_helper] = new $helper;  
        $this->helper[$lc_helper] = $helper_arr[$lc_helper];    
    }
}

//我在 Controller 中这样调用函数

Class Home Extends Controller   {

    $this->load_helper('Form');

    $this->helper['form']-><class function>;
}

我想这样调用函数:

$this->form-><class function>;

我不能对公共(public)函数使用提取，但我见过可以做到这一点的框架。

我希望有人有想法并且有人可以理解我的问题，在此先感谢。

Answer 1

看看魔法__get方法。来自文档:

Overloading in PHP provides means to dynamically "create" properties and methods. These dynamic entities are processed via magic methods one can establish in a class for various action types.

The overloading methods are invoked when interacting with properties or methods that have not been declared or are not visible in the current scope. The rest of this section will use the terms "inaccessible properties" and "inaccessible methods" to refer to this combination of declaration and visibility.

例如可以这样实现:

class Controller {
    public $helper = [];

    public function load_helper($helper)    {
        require_once(DIR_HELPER . $helper . '.php');
        $lc_helper = StrToLower($helper);
        $helper_arr[$lc_helper] = new $helper;  
        $this->helper[$lc_helper] = $helper_arr[$lc_helper];    
    }

    public function __get($property) {
        //Load helper if not exists
        if (!isset($this->helper[$property])) {
            $this->load_helper($property);
        }

        //Return the helper
        return $this->helper[$property];
    }
}

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旁注:

Controller::$helper 和 Controller::load_helper() 在我的理解中应该是 private 或 protected 而不是 public。