whoa.scala

  def of[F[_]](pf: PartialFunction[Request[F], HttpRoutes[F]])(
      implicit F: Sync[F]): HttpRoutes[F] = {
    Kleisli { req: Request[F] =>
      OptionT.fromOption[F](pf.lift(req).map(_.apply(req))).flatMap(identity)
    }
  }

  // but we'd like to do multiple PartialFunctions here actually?
  // and a PF is already a Kleisli of Option
  def apply[F[_]: Monad, UserId](
      f: Kleisli[F, Request[F], Option[HttpRoutes[F]]]): HttpRoutes[F] = {
    Kleisli { request: Request[F] =>
      OptionT
        .liftF(f(request))
        .map(_.map(_.apply(request)))
        .flatMap(x => OptionT.fromOption[F](x))
        .flatMap(identity)
    }
  }