class student{  def sayHello(name: => String){    println(s"Hello, $name, welcome $name")  }}object FunctionDemo3 {  def main(args: Array[String]): Unit = {    val s = new student()    def getSName(s: String): String = {println("call"); s}    //传名参数    s.sayHello("Sky")    s.sayHello(getSName("Sky"))  }}

Hello, Sky, welcome SkycallcallHello, Sky, welcome Sky