For func

func.scala

// scalaは言わずものかな
val f:Int => Int = args.headOption match {
    case Some(value) => x => + catching(classOf[NumberFormatException]).opt(value.toInt).getOrElse(0)
    case None => x => x
}

    // そもそも宣言で型がわかっているので
val f1:Int => Int = args.headOption match {
    case Some(value) => _ + catching(classOf[NumberFormatException]).opt(value.toInt).getOrElse(0)
    case None => _
}