nyan.scala

case class Nyan(name:String, age:Int)

val nyans:List[Nyan] = List(Nyan("ねこがた", 2), Nyan("うーねこ", 4))

val has_wneko:List[Nyan] => Unit = l => l match {
  case Nil => println("うーねこのっといんざりすとなうよー")
  case Nyan("うーねこ", _) :: _ => println("うーねこいんざりすとなうよー")
  case _ :: rest => has_wneko(rest)
}

has_wneko(nyans)