从闭包中访问私有变量 [英] Accessing private variables from within a closure

问题描述

我试图引用一个闭包中的对象的私有变量。下面的代码似乎工作，但它抱怨致命错误：不能访问self ::当在第12行test.php没有活动的范围和致命错误：在第20行的test.php中不在对象上下文中时使用$ this

I'm trying to reference a private variable of an object from within a closure. The code below would seem to work, but it complains Fatal error: Cannot access self:: when no class scope is active in test.php on line 12 and Fatal error: Using $this when not in object context in test.php on line 20.

任何想法如何完成结果使用闭包，同时保持变量私有和没有帮助函数（击败整个想法的私有变量）。

Any ideas how to accomplish the same results using a closure while keeping the variables private and without making helper functions (defeating the whole idea of a private variable).

class MyClass
{

    static private $_var1;
    private $_var2;

    static function setVar1( $value )
    {
        $closure = function () use ( $value ) {
            self::$_var1 = $value;
        };
        $closure();
    }

    function setVar2( $value )
    {
        $closure = function () use ( $value ) {
            $this->_var2 = $value;
        };
        $closure();
    }

}

MyClass::setVar1( "hello" ); //doesn't work

$myclass = new MyClass;
$myclass->setVar2( "hello" ); //doesn't work

推荐答案

注意，此答案最初适用于 PHP5.3 及更早版本，现在可以使用。有关当前信息，请参阅此答案。

Edit to note, this answer was originally meant for PHP5.3 and earlier, it's possible now. For current information, see this answer.

这是不可能的。

但是，您可以使用引用：

You can, however, use references:

<?php
class MyClass
{

    static private $_var1;
    private $_var2;

    static function setVar1( $value )
    {
        $field =& self::$_var1;
        $closure = function () use ( $value,  &$field ) {
            $field = $value;
        };
        $closure();
    }

    function setVar2( $value )
    {
        $field =& $this->_var2;
        $closure = function () use ( $value, &$field ) {
            $field = $value;
        };
        $closure();
    }

}

MyClass::setVar1( "hello" );

$myclass = new MyClass;
$myclass->setVar2( "hello" );

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