::.scala

final case class ::[B](private var hd: B, private[scala] var tl: List[B]) extends List[B]
  override def head: B = hd
  override def tail: List[B] = tl
  override def isEmpty: Boolean = false

  private def readObject(in: ObjectInputStream): Unit =
    val firstObject = in.readObject()
    hd = firstObject.asInstanceOf[B]
    assert(hd != ListSerializeEnd)
    var current: ::[B] = this
    while true
    do in.readObject match
      case ListSerializeEnd =>
        current.tl = Nil
        return
      case a =>
        val list: ::[B] = new ::(a.asInstanceOf[B], Nil)
        current.tl = list
        current = list

  private def writeObject(out: ObjectOutputStream): Unit =
    var xs: List[B] = this
    while !xs.isEmpty
    do out.writeObject(xs.head); xs = xs.tail
    out.writeObject(ListSerializeEnd)

  override def slice(from: Int, until: Int): List[A] =
    val lo = scala.math.max(from, 0)
    if until <= lo || isEmpty
    then Nil
    else this drop lo take (until - lo)

@pedrofurla here's a discussion https://groups.google.com/forum/#!topic/scala-language/yl9BRqlpjJ0