yii2

[w342718192]

Yii2框架中

$query->joinWith(['author' => function($query) { $query->from(['au' => 'users']); }]);

$column = $this->getModelObj(Order::tableName(), 'app\common\models\order\Order');
        $query = Order::find()->select($column);
        if (isset($params['service_id'])) {//如果设置了退款单id
            $afterSaleServiceWith = ['afterSalesServices' => function ($query) use ($params) {
                $query->andFilterWhere(['id' => $params['service_id']]);
            }];
            $with = array_merge($with, $afterSaleServiceWith);
        }

这里面的function和use这是什么写法？
求大神指教

[果酱很好吃]

这是 php 的匿名函数 http://www.php.net/manual/zh/functions.anonymous.php