-- Author: Andy Stewart <lazycat.manatee@gmail.com> -- Maintainer: Andy Stewart <lazycat.manatee@gmail.com> -- -- Copyright (C) 2010 Andy Stewart, all rights reserved. -- -- This program is free software: you can redistribute it and/or modify -- it under the terms of the GNU General Public License as published by -- the Free Software Foundation, either version 3 of the License, or -- any later version. -- -- This program is distributed in the hope that it will be useful, -- but WITHOUT ANY WARRANTY; without even the implied warranty of -- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -- GNU General Public License for more details. -- -- You should have received a copy of the GNU General Public License -- along with this program. If not, see <http://www.gnu.org/licenses/>. module Manatee.Toolkit.General.Either where -- | Map left. mapLeft :: (t1 -> a) -> Either t1 t -> Either a t mapLeft _ (Right a) = Right a mapLeft f (Left a) = Left (f a) -- | Map right. mapRight :: (t1 -> b) -> Either t t1 -> Either t b mapRight _ (Left a) = Left a mapRight f (Right a) = Right (f a) -- | Apply either left. applyEitherLeft :: (a -> c) -> Either a b -> Maybe c applyEitherLeft f (Left l) = Just $ f l applyEitherLeft _ (Right _) = Nothing -- | Apply either right. applyEitherRight :: (b -> c) -> Either a b -> Maybe c applyEitherRight _ (Left _) = Nothing applyEitherRight f (Right r) = Just $ f r