php的匿名函数的bindTo()方法
简单来说这个方法主要是修改匿名函数的作用于范围的

比如:

<?php

class A {
    private $val;
    function __construct($val) {
        $this->val = $val;
    }
    function getClosure() {
        //returns closure bound to this object and scope
        return function() { return $this->val; };
    }
}

$ob1 = new A(1);
$ob2 = new A(2);

$cl = $ob1->getClosure();
echo $cl(), "\n";
$cl = $cl->bindTo($ob2);
echo $cl(), "\n";
?>

会输出:
1
2