9e8a12f2112b / MaybeDivideable

MaybeDivideable.scala

sealed trait MaybeDivideable {
  def get: Int //Extraction
  def flatMap(f: Int => MaybeDivideable): MaybeDivideable
}

object MaybeDivideable {
  def apply(value: Int): MaybeDivideable = 
      if (value == 0) UnDivideable else Divideable(value) // Lifting
}

case class Divideable(value: Int) extends MaybeDivideable {
  require(value != 0, "value must not be 0")

  override def get: Int = value
  override def flatMap(f: Int => MaybeDivideable): MaybeDivideable = f(get)
}

case object UnDivideable extends MaybeDivideable {
  override def get: Int = throw new NoSuchFieldException
  override def flatMap(f: Int => MaybeDivideable): MaybeDivideable = UnDivideable
}