gistfile1.scala

class Age private (val v: Short) extends AnyVal {
  def isInfant = v < 2
  def isToddler = v >= 2 && v <= 4
  def isSenior = v >= 50
}

object Age {
  def apply(v: Short): Age = {
    require(v >= 0 && v < 200, "Must be between 0 and 200")
    new Age(v)
  }
}