关于Closure :: bind的PHP文档中的示例包括匿名函数声明中的static.为什么？如果删除它,我找不到区别.
有：
class A { private static $sfoo = 1; }
$cl1 = static function() { return self::$sfoo; }; // notice the "static"
$bcl1 = Closure::bind($cl1,null,'A');
echo $bcl1(); // output: 1
无：
class A { private static $sfoo = 1; }
$cl1 = function() { return self::$sfoo; };
$bcl1 = Closure::bind($cl1,'A');
echo $bcl1(); // output: 1
