readme.md

http://miyatin.hatenablog.com/entry/2015/03/27/085605

FlipFlapper.scala

trait FlipFlapper[T] {
  def doFlipFlap(x: T): T
}

object FlipFlapper {
  def fromFunction[A](f: A => A): FlipFlapper[A] =
    new FlipFlapper[A] {
      def doFlipFlap(x: A) = f(x)
    }

  implicit val int =
    fromFunction[Int](- _)

  implicit val string =
    fromFunction[String](_.reverse)

  implicit def list[A] =
    fromFunction[List[A]](_.reverse)

  implicit val boolean =
    fromFunction[Boolean](! _)
}