Node.scala

trait Node {
  var prev : Node = null
  var next : Node = null

  def ✂ : Node = { delete }
  def unary_~ : Node = { delete }
  def ⇠ : Node = { prev }
  def ⇢ : Node = { next }
  def ⇠? : Boolean = { prev == null }
  def ⇢? : Boolean = { prev == null }
  def ⇠(item : Node) : Node = { prev(item) }
  def ⇢(item : Node) : Node = { next(item) }

  def delete : Node = {
    if(next != null) {
      next.prev = prev
      next = null
    }

    if(prev != null) {
      prev.next = next
      prev = null
    }

    this
  }

  def next(item : Node) : Node = {
    item.prev = this
    next = item
    next
  }

  def prev(item : Node) : Node = {
    item.next = this
    prev = item
    prev
  }
}

class LinkedString extends Node { var data : String = _ }
object LinkedString {
  def apply(str : String) : LinkedString = {
    var l = new LinkedString
    l.data = str
    return l
  }
}

object Driver {
    def main(args : Array[String]) = {
        val h = new LinkedString("Hello")
        val w = new LinkedString("World")
        val p = new LinkedString("!")
        h ⇢ w ⇢ p
        printf("%s %s%s%n", h.data, h.⇢.asInstanceOf[LinkedString].data, h.⇢.⇢.asInstanceOf[LinkedString].data)
        h.✂ // h ✂; is also valid, but h ✂ is not.
        printf("%s %s%n", h.data, h.⇢)
        h next w
        printf("%s %s%n", h.data, h.⇢.asInstanceOf[LinkedString].data)
        ~h
    }
}

scala> Driver.main(Array[String]())
Hello World!
Hello null
Hello World