TraverseFreestyle.scala

import cats.Id
import cats.implicits._
import freestyle._
import freestyle.implicits._

import scala.concurrent.ExecutionContext.Implicits.global
import scala.concurrent.Future

/**
  * Created by abdhesh on 05/05/17.
  */
object TraverseFreestyle extends App {


    @free trait Calc {
      def sum(a: Int, b: Int): FS[Int]

      def product(a: Int, b: Int): FS[Int]
    }

    implicit val idHandler = new Calc.Handler[Id] {
      def sum(a: Int, b: Int): Id[Int] = a + b

      def product(a: Int, b: Int): Id[Int] = a * b
    }


    implicit val futureHandler = new Calc.Handler[Future] {
      def sum(a: Int, b: Int): Future[Int] =
        Future {
          Thread.sleep(a * 100L);
          a + b
        }

      def product(a: Int, b: Int): Future[Int] =
        Future {
          Thread.sleep(a * 100L);
          a * b
        }
    }

  val incrPar: Int => FreeS.Par[Calc.Op, Int] = Calc[Calc.Op].sum(_, 1)

  val incrSeq: Int => FreeS[Calc.Op, Int] = incrPar.andThen(_.freeS)

  val numbers = List.range(1, 10)

  val traversingPar = numbers.traverseU(f => incrPar(f))
  val traversingSeq = numbers.traverseU(incrSeq)

  traversingPar.interpret[Id]

  traversingSeq.interpret[Id]
}