lift

lift.scala

import cats._, cats.data._, cats.implicits._
import scala.concurrent.Future
import scala.concurrent.ExecutionContext.Implicits.global
import scala.concurrent.{Await, duration}

object Main extends App {
  implicit class Ops[In](in: In) {
    def |>[Out](f: In => Out): Out = f(in)
  }

  def liftFutureOption[A](f: Future[Option[A]]) = OptionT(f)
  def liftFuture[A](f: Future[A]) = OptionT.liftF(f)
  def liftOption[A](o: Option[A]) = OptionT(o.pure[Future])
  def lift[A](a: A) = liftOption(Some(a))

  def getA = Future.successful(Some(1))
  def getB = Future.successful(Some(2))
  def getC = Future.successful(3)
  def getD = Some(4)

  val result = for {
    a <- getA |> liftFutureOption
    b <- getB |> liftFutureOption
    c <- getC |> liftFuture
    d <- getD |> liftOption
    e <- 10   |> lift
  } yield e * (a * b) / (c * d)

  println(Await.result(result.value, duration.Duration.Inf))
}