Data.Either.HT
mapLeft :: (a -> b) -> Either a c -> Either b c #
mapRight :: (b -> c) -> Either a b -> Either a c #
mapBoth :: (a -> c) -> (b -> d) -> Either a b -> Either c d #
maybeLeft :: Either a b -> Maybe a #
maybeRight :: Either a b -> Maybe b #
swap :: Either a b -> Either b a #