implicit val jsResultApplicative = new Applicative[JsResult] {
    override def point[A](t: => A) = jsSuccess(t)

    override def ap[A,B](fa: => JsResult[A])(f: => JsResult[A => B]) =
      f match {
        case JsSuccess(f, path) => fa.map(f)  // XXX: is it correct to ignore path?
        case JsError(x) => JsError(x)
      }
  }