2019-06-24から1日間の記事一覧
> :{ *| foo :: MonadThrow m => Int -> m Int *| foo x = (if x == 0 then throwM RatioZeroDenominator else return x) *| :} > :t foo foo :: MonadThrow m => Int -> m Int IOの場合 > foo 1 :: IO Int 1 > foo 0 :: IO Int *** Exception: Ratio has ze…