clojurelist.scala

object Test {
  type List[A] = Option[Cons[A]]
  final case class Cons[A](hd: A, tl: Option[Cons[A]]) {
    def nth(n: Int): A = if (n == 1) hd else tl.get nth n - 1
  }

  def list[A](xs: A*): List[A]  = if (xs.isEmpty) None else Some(Cons(xs.head, list(xs.tail: _*)))
  def single[A](hd: A): Cons[A] = Cons(hd, None)

  // (nth (rest (cons 1 nil)) 1)
  def lhs = single(1).tl map (_ nth 1)

  // (nth nil 1)
  def rhs = list[Int]() map (_ nth 1)

  def main(argv: Array[String]): Unit = {
    // (nth (rest (cons 1 nil)) 1) == (nth nil 1)
    assert(lhs == rhs)
  }
}