Scala:部分函数错误:如果要将其视为部分函数，请使用 _

Question

以下代码段不起作用：FileSystems.getDefault.getPath 来自 java.nio 包

更新：

方法创建计算为：

注意：MyLocation 是一个扩展 MyMessage 的案例类

def creatCalculation(myPlace: MyLocation): MyMessage = {
    if (some test) {
       //--- some code
    } else
       MyError("My Calculation already done")
        MyAck //returning the case object MyAck which is of type MyMessage
  }

/

/Req 是来自： net.liftweb.http.Req 的类

val someVal: PartialFunction[Req, () => Box[LiftResponse]] {
case "create" :: Nil JsonPostAndApproval s =>
          postResponse(s, (j: JValue, p: Permissions, r: Req) => {
        createCalculation(fromJValue[MyLocation](j) = {
          case "MyAck" => {
             val myCalculator: Calculator = new Calculator(FileSystems.getDefault.getPath(fromJsonVal[MyLocation](s._1).path))
             val resultsMap = myCalculator.foreach( (p) => Map[String,  Int])
                 for( (myKey, myValue) <- resultsMap) {
                    printf("key: %s, value:  %sn", myKey, myValue)
                 }
          }
        })
      } ) ("Failed to calculate")
 }

编译器像这样抱怨：

[error] C:UsersluluExampleHandler.scala:129: missing arguments for
method fromJValue in package json;
[error] follow this method with `_' if you want to treat it as a partially applied function
[error]         createCalculation(fromJsonVal[MyLocation](j) = {
[error]                                  ^

这是 fromJsonVal 的方法定义

/**
   * Routine to convert JValue to native type
   *
   * @param in JValue to convert
   * @tparam T native type to extract
   * @return extracted native type
   */
  def fromJsonVal[T: Manifest](in: JValue): T = in.extract[T]

JValue 来自 net.liftweb/json，是：密封抽象类 JValue（）extend java.lang.Object with net.liftweb.json.Diff.Diffable { <>}

更新：编译器报告此行代码中的错误

你认为我应该如何纠正这个编译错误？

   createCalculation(fromJValue[MyLocation](j) = {

Answer 1

如果没有全貌，我认为错误只是因为您试图将输出分配给方法和缺少参数。如果没有全貌，我的猜测是你正在寻找更像的东西：

createCalculation(fromJValue[MyLocation](j)) match {
  case "MyAck"....

注意j后的双帕伦