sealed abstract class ShowUnapproved {
  def shallShow(post: Post): Boolean // a "post" is e.g. a comment
}


object ShowUnapproved {

  case object None extends ShowUnapproved {
    override def shallShow(post: Post) =
      post.someVersionApproved
  }

  case object All extends ShowUnapproved {
    override def shallShow(post: Post) = true
  }

  case class WrittenByUser(userId: String) extends ShowUnapproved {
    override def shallShow(post: Post) =
      post.userId == userId
  }
}

PageReneder.renderPage(page, ShowUnapproved.All)
PageReneder.renderPage(page, ShowUnapproved.WrittenByUser(userId))

val showUnapproved = ...  // sounds like a Boolean but it is not

val anyPendingApprovalText: NodeSeq =
  if (showUnapproved.shallShow(post)) makePendingApprovalText(post)
  else Nil
  // does `showUnapproved.shallShow` above sound good to you?

sealed abstract class CommentVisibility {
  def shallShow(comment: Comment): Boolean
}

object CommentVisibility {
  case object HideUnapproved
  case object ShowUnapproved
  case class ShowAllByUser(userId)
}

renderPage(page, CommentVisibility.ShowUnapproved)