object Heltal {
  def unapply(x: String): Option[Int] = try {
    Some(x.toInt)
  } catch {
    case e: NumberFormatException => None
  }
}

def runMatch(s: String) = s match {
  case Heltal(x) => println(x + 1)
  case _         => println("NaN")
}

@ runMatch("hi")
NaN

@ runMatch("10")
11