ZIO Kleisli

ZKleisli.scala

package zio

case class ZKleisli[-R, +E, -A, +B](
    run: A => ZIO[R, E, B]
) { self =>
  // compose with a ZIO not lifted into a Kleisli
  def mapZIO[R1 <: R, E1 >: E, A1 <: A, C1](bc: B => ZIO[R1, E1, C1]): ZKleisli[R1, E1, A, C1] =
    ZKleisli(self.run(_).flatMap(bc))

  // Modify the output of the Kleisli function with `f`
  def map[C](f: B => C): ZKleisli[R, E, A, C] = ZKleisli(self.run(_).map(f))

  // arrow composition tip to tail
  def andThen[R1 <: R, E1 >: E, C](
      f: ZKleisli[R1, E1, B, C]
  ): ZKleisli[R1, E1, A, C] =
    ZKleisli(self.run(_).flatMap(f.run(_)))
}