Agda-2.6.0: A dependently typed functional programming language and proof assistant

Agda.Utils.Either

Description

Utilities for the Either type.

Synopsis

# 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.

mapEither :: (a -> c) -> (b -> d) -> Either a b -> Either c d Source #

Either is a bifunctor.

mapLeft :: (a -> c) -> Either a b -> Either c b Source #

'Either _ b' is a functor.

mapRight :: (b -> d) -> Either a b -> Either a d Source #

'Either a' is a functor.

traverseEither :: Functor f => (a -> f c) -> (b -> f d) -> Either a b -> f (Either c d) Source #

Either is bitraversable.

isRight :: Either a b -> Bool Source #

Returns True iff the argument is Right x for some x.

Note: from base >= 4.7.0.0 already present in Data.Either.

isLeft :: Either a b -> Bool Source #

Returns True iff the argument is Left x for some x.

Note: from base >= 4.7.0.0 already present in Data.Either.

fromLeft :: (b -> a) -> Either a b -> a Source #

Analogue of fromMaybe.

fromRight :: (a -> b) -> Either a b -> b Source #

Analogue of fromMaybe.

fromLeftM :: Monad m => (b -> m a) -> m (Either a b) -> m a Source #

Analogue of fromMaybeM.

fromRightM :: Monad m => (a -> m b) -> m (Either a b) -> m b Source #

Analogue of fromMaybeM.

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 Just input_with_tags_stripped if all elements are to the Left, and otherwise Nothing.

allRight :: [Either a b] -> Maybe [b] Source #

Returns Just input_with_tags_stripped if all elements are to the right, and otherwise Nothing.

 allRight xs ==
if all isRight xs then
Just (map ((Right x) -> x) xs)
else
Nothing


maybeToEither :: Maybe a -> Either () a Source #

Convert Maybe to Either ().