Linked List Using Scala

LinkedList.scala

package linkedlist


sealed trait AbstractCons[+A] {
  def value: A

  def next: AbstractCons[A]
}

/**
  * cons class 
  * @param value
  * @param next
  * @tparam A
  */
case class Cons[+A](value: A, next: AbstractCons[A]) extends AbstractCons[A] {
  override def toString = s"head: $value, next: $next"
}

/**
  * Nil to indicate end of list
  */
object NilCons extends AbstractCons[Nothing] {
  def value = throw new NoSuchElementException("it is empty")

  def next = throw new UnsupportedOperationException("tail of empty list")
}

/**
  * example to run the linked list
  */
object LinkedList extends App {

  /**
    * Operation :: for Any
    * @param value1
    * @tparam A
    */
  implicit class ConsAny[+A](value1: A) {
    def ::[A](value2: A) = Cons(value2, Cons(value1, NilCons))
  }

  /**
    * Operation :: for AbstractCons
    * @param value1
    * @tparam A
    */
  implicit class ConsOps[+A](value1: AbstractCons[A]) {
    def ::[A](value2: A) = Cons(value2, value1)
  }

  val linkedList: Cons[Any] =("test1")::("test2")::("test3")::("test4")

  println(linkedList)
}