りふぁくた fold => emap

この指摘２回目では・・・・

foldでかくと

Future.successful(Option(1)).flatMap(fold(Future.failed(new Exception("e")))(v => Future.successful(v)))

scalaz

Future.successful(Option(1)) emap (_ \/> new Exception("e"))

うーんなぁ・・・ぐやじぃ

型推論させる

Future.successful(Option(1)).flatMap(_.map(Future.successful).getOrElse(Future.failed(new Exception("e"))))