编辑代码

object Hello extends App {
    println("Hello world!     -  scala.jsrun.net")

    for (_ <- 1 to 3) { println("ho ") } 

    val sample = new sample
    +sample
    -sample
    !sample
    ~sample
}

class sample {

    def unary_+ :Unit = println("call unary +")
    def unary_- :Unit = println("call unary -")
    def unary_! :Unit = println("call unary !")
    def unary_~ :Unit = println("call unary ~")

}