propella https://blog.hatena.ne.jp/propella/ 言語ゲーム https://propella.hatenablog.com/ import Control.Arrow newtype SF a b = SF {runSF ::[a]->[b]} instance Arrow SF where arr f = SF (map f) SF f >>> SF g = SF (f >>> g) first (SF f) = SF (unzip >>> first f >>> uncurry zip) instance ArrowChoice SF where left (SF f) = SF(\xs -> combine xs (f [y | Left y <- xs])) where combine (Left y:xs)… 190 <iframe src="https://hatenablog-parts.com/embed?url=https%3A%2F%2Fpropella.hatenablog.com%2Fentry%2F20070808%2Fp1" title=" [haskell] How To Arrow3 選択 - 言語ゲーム" 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 2007-08-08 00:00:00 rich https://propella.hatenablog.com/entry/20070808/p1 1.0 100%