Safe Haskell | Safe |
---|---|
Language | Haskell98 |
Utilities for the Either
type
- whileLeft :: Monad m => (a -> Either b c) -> (a -> b -> m a) -> (a -> c -> m d) -> a -> m d
- caseEitherM :: Monad m => m (Either a b) -> (a -> m c) -> (b -> m c) -> m c
- mapEither :: (a -> c) -> (b -> d) -> Either a b -> Either c d
- mapLeft :: (a -> c) -> Either a b -> Either c b
- mapRight :: (b -> d) -> Either a b -> Either a d
- traverseEither :: Functor f => (a -> f c) -> (b -> f d) -> Either a b -> f (Either c d)
- isLeft :: Either a b -> Bool
- isRight :: Either a b -> Bool
- fromLeft :: (b -> a) -> Either a b -> a
- fromRight :: (a -> b) -> Either a b -> b
- maybeLeft :: Either a b -> Maybe a
- maybeRight :: Either a b -> Maybe b
- allLeft :: [Either a b] -> Maybe [a]
- allRight :: [Either a b] -> Maybe [b]
- tests :: IO Bool
Documentation
whileLeft :: Monad m => (a -> Either b c) -> (a -> b -> m a) -> (a -> c -> m d) -> a -> m d Source
Loop while we have an exception.
caseEitherM :: Monad m => m (Either a b) -> (a -> m c) -> (b -> m c) -> m c Source
Monadic version of either
with a different argument ordering.
traverseEither :: Functor f => (a -> f c) -> (b -> f d) -> Either a b -> f (Either c d) Source
Either
is bitraversable.
maybeLeft :: Either a b -> Maybe a Source
Safe projection from Left
.
maybeLeft (Left a) = Just a
maybeLeft Right{} = Nothing
maybeRight :: Either a b -> Maybe b Source
Safe projection from Right
.
maybeRight (Right b) = Just b
maybeRight Left{} = Nothing
allLeft :: [Either a b] -> Maybe [a] Source
Returns
if all elements are
to the Just
with tags strippedLeft
, and otherwise Nothing
.