comonadTupoOI.scala

case class TupoOI[A](a: A, inputs: Stream[String]) {
  def copoint: A = a
  def map[B](fun: A => B): TupoOI[B] = TupoOI(fun(a), inputs)
  def coflatMap[B](fun: TupoOI[A] => B): TupoOI[B] = {
    TupoOI(fun(this), inputs.tail)
  }
  override def toString = a.toString
}

object comonadTupoOI {

  def a(x: String): Double = { readLine; x.toDouble }
  def b(y: Double): Int = { readLine; y.toInt }

  def fa(x: TupoOI[String]): Double = x.copoint.toDouble
  def fb(y: TupoOI[Double]): Int = y.copoint.toInt

  def main(args: Array[String]) {
    println((a _ andThen b _)("1.1"))

    import TupoOI._
    val inputs = Stream(readLine, readLine)
    println(TupoOI("1.1", inputs).coflatMap(fa).coflatMap(fb))
  }
}