如何将PartialFunction与另一个函数组合并返回PartialFunction？

Question

我有以下类：

class MessageProcessorActor(private val destination : ActorRef) extends Actor{
  override def receive: Receive = {
    case _ =>
    destination ! {
      case MyActor.TracableMessage(msg) => MyActor.TracableMessage("Processed + " + msg)
      case MyActor.Message(msg) => MyActor.Message("Processed + " + msg)
      case _ => "Processed + " + _
    }(_)
  }
}

object MyActor{
  case class TracableMessage(private val msg: String) extends Message(msg)
  case class Message(private val msg: String)
}

其中Recieve定义为

type Receive = PartialFunction[Any, Unit]

在这里，我试图避免声明持有PartialFunction[Any, Any]的val，而是这样调用它。但是编译器拒绝了这个代码。它打印：

Error:(12, 6) ';' expected but '(' found.
    }(_)
     ^

有没有做这样的事情的捷径？

Answer 1

你为什么要试着这样写呢？关注有什么问题吗？

class MessageProcessorActor(private val destination : ActorRef) extends Actor{
  override def receive: Receive = {
    case MyActor.TracableMessage(msg) => {
      destination ! MyActor.TracableMessage("Processed + " + msg)
    }
    case MyActor.Message(msg) => {
      destination ! MyActor.Message("Processed + " + msg)
    }
    case _ => { 
      destination ! "Processed + " + _
    }
  }
}

object MyActor{
  case class TracableMessage(private val msg: String) extends Message(msg)
  case class Message(private val msg: String)
}