scala – 在地图中进行懒惰评估

我正在尝试根据输入创建一个执行其他函数(返回字符串)的函数.
例如：

def execute(input: String) = {
    val actions = Map("foo" -> someObject.doStuff(),"bar" -> someObject.doThing())
    actions.get(input) }

有没有办法只在相应的密钥存在时才能调用Map中的函数？

解决方法

object someObject {
  def doStuff() = "foo"
  def doThing() = "bar"

}

//if you need a string as a return value.
//there will be empty string for missing keys
def execute(input: String):String = {
  val actions = Map( "foo" -> someObject.doStuff _,"bar" -> someObject.doThing _ )

  actions.getorElse(input,()=>"")()
}


//if you need an Option[String] as a return value.
//there will be None value for missing keys
def executeOption(input: String):Option[String] = {
  val actions = Map( "foo" -> someObject.doStuff _,"bar" -> someObject.doThing _ )

  actions.get(input).map(_())
}