xuwei https://blog.hatena.ne.jp/xuwei/ xuwei-k's blog https://xuwei-k.hatenablog.com/ haskell scala scalaz まず、下記の10行程度のScalaコードをご覧ください sealed abstract class Foo[A, B] final case class X[A]() extends Foo[A, A] final case class Y[A, B](a: A, b: B) extends Foo[A, B] object Main { def hoge[F[_, _], A, B, C](foo: Foo[A, B], bar: F[A, C]): F[B, C] = foo match { case X() => bar case Y(a, b) => ??? // Yの場合のコードはど… 190 <iframe src="https://hatenablog-parts.com/embed?url=https%3A%2F%2Fxuwei-k.hatenablog.com%2Fentry%2F20140706%2F1404612620" title="HaskellのGADTsすごいなーと思ったのと、それをscalaz.Leibniz使って頑張る話 - xuwei-k&#39;s blog" class="embed-card embed-blogcard" scrolling="no" frameborder="0" style="display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;"></iframe> Hatena Blog https://hatena.blog 2014-07-06 11:10:20 rich https://xuwei-k.hatenablog.com/entry/20140706/1404612620 1.0 100%