example.scala

type ActionCont[T] = EitherT[Future, UseCaseResult, A]

final class FindWarriorImpl[Ctx <: IOContext](
  ctx: Ctx,
  repository: WarriorRepository[Future]
) extends FindWarrior {
  def apply(id: WarriorId): ActionCont[Warrior] = EitherT {
    repository.resolveBy(id) map {
      case Some(w) => Right(w)
      case None => Left(WarriorNotFound)
    }
  }
}