gistfile1.scala

  case object ArticleNotFound

  trait ArticleService {
    def getArticleDetails(articleId: Long): Future[\/[ArticleNotFound.type, ArticleDetails]]
    def getArticleIdByUniqueName(articleName: String): Future[\/[ArticleNotFound.type, Long]]
  }

  def getArticleDetails(articleName: String): Future[\/[ArticleNotFound.type, ArticleDetails]] = {
    for {
      articleId <- articleService.getArticleIdByUniqueName(articleName)
      article <- articleService.getArticleDetails(articleId)
    } yield article
  }