元ネタ わーい、すごーい タイトルの元ネタ 4話のサーバルちゃんの「砂がたくさんあるねー！」 『けものフレンズ』4話、サーバルちゃんのあるセリフがすごく深い「見落としてるものを気づかせてくれる」 Stateモナド 戻り値と一緒に返した状態を引き回せるモナドなんだね！すごーい！ import Control.Monad.State (State, modify, execState) type Friends = State String () wai :: Friends wai = modify (++ "わーい！\n") sugoi :: Friends sugoi = modify (++ "すごーい！\n") tanoshii :: Friends tanoshii = modify (++ "たーのしー！\n") friends :: String -> Friends frie

Better Exception Messages Published February 16, 2017 Better exception messages Let's write a really silly, highly inefficient (my favorite kind!) program that connects to multiple HTTP servers and sends a very simple request. Using the network package, this is really straightforward: #!/usr/bin/env stack -- stack --install-ghc --resolver lts-8.0 runghc --package network -- -Wall -Werror import Co