Scala example source code file (simplelists.scala)

This example Scala source code file (simplelists.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

cons, cons, list, list, nil, nil, nothing, nothing, string

The Scala simplelists.scala source code

abstract class List[+a] {
  def head: a
  def tail: List[a]
  def cons[b >: a](x: b): List[b] = new Cons[b, a](x, this)
}

object Nil extends List[Nothing] {
  def error(msg: String): Nothing = throw new java.lang.Error(msg)
  def head: Nothing = error("Nil.head")
  def tail: List[Nothing] = error("Nil.tail")
}

class Cons[c, d <: c](x: c, xs: List[d]) extends List[c] {
  def head: c = x
  def tail: List[c] = xs
}