案件

我正在玩一个 Laravel 项目，看看是否可以使用闭包来实现排序接口，我注意到当我dd()闭包时，它还显示了将闭包创建为属性的类。

最小化代码

// in my Order model class, i have a function that will return a closure\npublic static function defaultSortFunction(){\n    $sortColumn = property_exists(self::class,'defaultSortingColumn') ? self::$defaultSortingColumn : 'created_at';\n\n    return function($p,$n)use($sortColumn){\n        return $p->$sortColumn <=> $n->$sortColumn;\n    };\n}\n

// in one of my controller I use for testing, I added these 2 methods for testing\npublic function index(){\n    $sortFunction = Order::defaultSortFunction();\n    $this->someOtherFunction($sortFunction);\n    return 'done';\n}\n\nprivate function someOtherFunction($fn){\n    dd($fn);\n\n    // $scopeModel = get_class($fn); => Closure\n    \n    // example …