Lesson5.scala

sealed trait H {
  def falsy: Boolean
}

case class A(b: Boolean) extends H {
  override def falsy = !b
}

case class C(d: Byte, more: H) extends H {
  override def falsy = d == 0 && more.falsy
}

case class E(f: A, g: C)


object Lesson5 {
  def main(args: Array[String]): Unit = {
    val a: A = A(true)
    val h1: H = a
    val h2: H = A(false)
    val h3: H = C(17)
    val h4: H = C(99)

    println(h1)
    println(h2)
    println(h3)
    println(h4)

    def doSomethingWithAnH(h: H) = h match {
      case A(b) =>
    }
  }

  val x: Any = "xx"
  val y: Nothing = x

  def m(letSay: Nothing): String = letSay

  def n(s: String): Any = s

  val z: Null = null
  val zz: String = z

  def falsyFunc(h: H): Boolean = h match {
    case A(b)       => !b
    case C(d, more) => d == 0 && falsyFunc(more)
  }
}