def main(args: Array[String]): Unit = {


    val stateProgram : IndexedStateT[Eval, Counter, Counter, Int] = for {
      _ <- increaseCount(10)
      count1 <- getCount
      _ <- increaseCount(5)
      count2 <- getCount
    } yield count1 + count2

    stateProgram.run(Counter(100)).map(state => IO(println(state))).value.unsafeRunSync()
  }

  case class Counter(int: Int = 0)

  def increaseCount(by: Int = 1): State[Counter, Unit] = State[Counter, Unit](counter =>
    (counter.copy(counter.int + by), ())
  )

  def getCount: State[Counter, Int] = State[Counter, Int](c => (c, c.int))