class Foo {
    def parse(list: List[String]) = list match {
        case "a" :: xs => xs match {
            case "b" :: ys => ys match {
                case "c" :: Nil => 1
                case _ => 0
            }
            case _ => 0
        }

        case "d" :: "e" :: "f" :: Nil => 2
        case _ => 0
    }
}