GeneralizedOrElse.scala

trait OrElseAble[F[_]] {
  def getOrElse[A, B >: A](fa: F[A])(orElse: => B): B
}

object OrElseAble {
  implicit val OptionElsable: OrElseAble[Option] = new OrElseAble[Option] {
    override def getOrElse[A, B >: A](fa: Option[A])(orElse: => B) = fa.getOrElse(b)
  }
  implicit val TryElsable: OrElseAble[Try] = new OrElseAble[Try] {
    override def getOrElse[A, B >: A](fa: Try[A])(orElse: => B) = fa.getOrElse(b)
  }
}

object FutureHelpers {
  
  def toFuture[A, F[_] : OrElseAble](fa: F[A])(onFailure: => Throwable): Future[A] =
    Future.successful(
      implicitly[OrElseAble[F]]
    ).map(_.getOrElse(fa)(throw onFailure))
  
  def toFuture[A, B >: A, F[_] : OrElseAble](fa: F[A])(onFailure: => B): Future[B] =
    Future.successful(
      implicitly[OrElseAble[F]].getOrElse(fa)(onFailure)
    )
}