Copyright	(c) 2006-2007 Roman Leshchinskiy (c) 2013 Simon Meier
License	BSD-style (see the file LICENSE)
Maintainer	Simon Meier <iridcode@gmail.com>
Stability	experimental
Portability	GHC
Safe Haskell	None
Language	Haskell2010

Data.Either.Strict

Description

The strict variant of the standard Haskell Either type and the corresponding variants of the functions from Data.Either.

Note that the strict Either type is not an applicative functor, and therefore also no monad. The reasons are the same as the ones for the strict Maybe type, which are explained in Data.Maybe.Strict.

Synopsis

data Either a b
- = Left !a
- | Right !b
isRight :: Either a b -> Bool
isLeft :: Either a b -> Bool
either :: (a -> c) -> (b -> c) -> Either a b -> c
lefts :: [Either a b] -> [a]
rights :: [Either a b] -> [b]
partitionEithers :: [Either a b] -> ([a], [b])
_Left :: Prism (Either a c) (Either b c) a b
_Right :: Prism (Either c a) (Either c b) a b

Documentation

data Either a b #

The strict choice type.

Constructors

Left !a
Right !b

Instances

Bifunctor Either
Instance details Defined in Data.Strict.Either Methods bimap :: (a -> b) -> (c -> d) -> Either a c -> Either b d # first :: (a -> b) -> Either a c -> Either b c # second :: (b -> c) -> Either a b -> Either a c #
Swap Either
Instance details Defined in Data.Strict.Either Methods swap :: Either a b -> Either b a #
Assoc Either
Instance details Defined in Data.Strict.Either Methods assoc :: Either (Either a b) c -> Either a (Either b c) # unassoc :: Either a (Either b c) -> Either (Either a b) c #
Bitraversable Either
Instance details Defined in Data.Strict.Either Methods bitraverse :: Applicative f => (a -> f c) -> (b -> f d) -> Either a b -> f (Either c d) #
Bifoldable Either
Instance details Defined in Data.Strict.Either Methods bifold :: Monoid m => Either m m -> m # bifoldMap :: Monoid m => (a -> m) -> (b -> m) -> Either a b -> m # bifoldr :: (a -> c -> c) -> (b -> c -> c) -> c -> Either a b -> c # bifoldl :: (c -> a -> c) -> (c -> b -> c) -> c -> Either a b -> c #
Eq2 Either
Instance details Defined in Data.Strict.Either Methods liftEq2 :: (a -> b -> Bool) -> (c -> d -> Bool) -> Either a c -> Either b d -> Bool #
Ord2 Either
Instance details Defined in Data.Strict.Either Methods liftCompare2 :: (a -> b -> Ordering) -> (c -> d -> Ordering) -> Either a c -> Either b d -> Ordering #
Read2 Either
Instance details Defined in Data.Strict.Either Methods liftReadsPrec2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> Int -> ReadS (Either a b) # liftReadList2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> ReadS [Either a b] # liftReadPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec (Either a b) # liftReadListPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec [Either a b] #
Show2 Either
Instance details Defined in Data.Strict.Either Methods liftShowsPrec2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> Int -> Either a b -> ShowS # liftShowList2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> [Either a b] -> ShowS #
NFData2 Either
Instance details Defined in Data.Strict.Either Methods liftRnf2 :: (a -> ()) -> (b -> ()) -> Either a b -> () #
Hashable2 Either
Instance details Defined in Data.Strict.Either Methods liftHashWithSalt2 :: (Int -> a -> Int) -> (Int -> b -> Int) -> Int -> Either a b -> Int #
Functor (Either a)
Instance details Defined in Data.Strict.Either Methods fmap :: (a0 -> b) -> Either a a0 -> Either a b # (<$) :: a0 -> Either a b -> Either a a0 #
Foldable (Either e)
Instance details Defined in Data.Strict.Either Methods fold :: Monoid m => Either e m -> m # foldMap :: Monoid m => (a -> m) -> Either e a -> m # foldr :: (a -> b -> b) -> b -> Either e a -> b # foldr' :: (a -> b -> b) -> b -> Either e a -> b # foldl :: (b -> a -> b) -> b -> Either e a -> b # foldl' :: (b -> a -> b) -> b -> Either e a -> b # foldr1 :: (a -> a -> a) -> Either e a -> a # foldl1 :: (a -> a -> a) -> Either e a -> a # toList :: Either e a -> [a] # null :: Either e a -> Bool # length :: Either e a -> Int # elem :: Eq a => a -> Either e a -> Bool # maximum :: Ord a => Either e a -> a # minimum :: Ord a => Either e a -> a # sum :: Num a => Either e a -> a # product :: Num a => Either e a -> a #
Traversable (Either e)
Instance details Defined in Data.Strict.Either Methods traverse :: Applicative f => (a -> f b) -> Either e a -> f (Either e b) # sequenceA :: Applicative f => Either e (f a) -> f (Either e a) # mapM :: Monad m => (a -> m b) -> Either e a -> m (Either e b) # sequence :: Monad m => Either e (m a) -> m (Either e a) #
Eq a => Eq1 (Either a)
Instance details Defined in Data.Strict.Either Methods liftEq :: (a0 -> b -> Bool) -> Either a a0 -> Either a b -> Bool #
Ord a => Ord1 (Either a)
Instance details Defined in Data.Strict.Either Methods liftCompare :: (a0 -> b -> Ordering) -> Either a a0 -> Either a b -> Ordering #
Read a => Read1 (Either a)
Instance details Defined in Data.Strict.Either Methods liftReadsPrec :: (Int -> ReadS a0) -> ReadS [a0] -> Int -> ReadS (Either a a0) # liftReadList :: (Int -> ReadS a0) -> ReadS [a0] -> ReadS [Either a a0] # liftReadPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec (Either a a0) # liftReadListPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec [Either a a0] #
Show a => Show1 (Either a)
Instance details Defined in Data.Strict.Either Methods liftShowsPrec :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> Int -> Either a a0 -> ShowS # liftShowList :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> [Either a a0] -> ShowS #
NFData a => NFData1 (Either a)
Instance details Defined in Data.Strict.Either Methods liftRnf :: (a0 -> ()) -> Either a a0 -> () #
Hashable a => Hashable1 (Either a)
Instance details Defined in Data.Strict.Either Methods liftHashWithSalt :: (Int -> a0 -> Int) -> Int -> Either a a0 -> Int #
Generic1 (Either a :: Type -> Type)
Instance details Defined in Data.Strict.Either Associated Types type Rep1 (Either a) :: k -> Type # Methods from1 :: Either a a0 -> Rep1 (Either a) a0 # to1 :: Rep1 (Either a) a0 -> Either a a0 #
(Eq a, Eq b) => Eq (Either a b)
Instance details Defined in Data.Strict.Either Methods (==) :: Either a b -> Either a b -> Bool # (/=) :: Either a b -> Either a b -> Bool #
(Data a, Data b) => Data (Either a b)
Instance details Defined in Data.Strict.Either Methods gfoldl :: (forall d b0. Data d => c (d -> b0) -> d -> c b0) -> (forall g. g -> c g) -> Either a b -> c (Either a b) # gunfold :: (forall b0 r. Data b0 => c (b0 -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Either a b) # toConstr :: Either a b -> Constr # dataTypeOf :: Either a b -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Either a b)) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Either a b)) # gmapT :: (forall b0. Data b0 => b0 -> b0) -> Either a b -> Either a b # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Either a b -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Either a b -> r # gmapQ :: (forall d. Data d => d -> u) -> Either a b -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Either a b -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Either a b -> m (Either a b) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Either a b -> m (Either a b) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Either a b -> m (Either a b) #
(Ord a, Ord b) => Ord (Either a b)
Instance details Defined in Data.Strict.Either Methods compare :: Either a b -> Either a b -> Ordering # (<) :: Either a b -> Either a b -> Bool # (<=) :: Either a b -> Either a b -> Bool # (>) :: Either a b -> Either a b -> Bool # (>=) :: Either a b -> Either a b -> Bool # max :: Either a b -> Either a b -> Either a b # min :: Either a b -> Either a b -> Either a b #
(Read a, Read b) => Read (Either a b)
Instance details Defined in Data.Strict.Either Methods readsPrec :: Int -> ReadS (Either a b) # readList :: ReadS [Either a b] # readPrec :: ReadPrec (Either a b) # readListPrec :: ReadPrec [Either a b] #
(Show a, Show b) => Show (Either a b)
Instance details Defined in Data.Strict.Either Methods showsPrec :: Int -> Either a b -> ShowS # show :: Either a b -> String # showList :: [Either a b] -> ShowS #
Generic (Either a b)
Instance details Defined in Data.Strict.Either Associated Types type Rep (Either a b) :: Type -> Type # Methods from :: Either a b -> Rep (Either a b) x # to :: Rep (Either a b) x -> Either a b #
Semigroup (Either a b)
Instance details Defined in Data.Strict.Either Methods (<>) :: Either a b -> Either a b -> Either a b # sconcat :: NonEmpty (Either a b) -> Either a b # stimes :: Integral b0 => b0 -> Either a b -> Either a b #
(Hashable a, Hashable b) => Hashable (Either a b)
Instance details Defined in Data.Strict.Either Methods hashWithSalt :: Int -> Either a b -> Int # hash :: Either a b -> Int #
(Binary a, Binary b) => Binary (Either a b)
Instance details Defined in Data.Strict.Either Methods put :: Either a b -> Put # get :: Get (Either a b) # putList :: [Either a b] -> Put #
(NFData a, NFData b) => NFData (Either a b)
Instance details Defined in Data.Strict.Either Methods rnf :: Either a b -> () #
type Rep1 (Either a :: Type -> Type)
Instance details Defined in Data.Strict.Either type Rep1 (Either a :: Type -> Type) = D1 (MetaData "Either" "Data.Strict.Either" "strict-0.4-DcORXBfkCIx3v5lLd1UYRe" False) (C1 (MetaCons "Left" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 a)) :+: C1 (MetaCons "Right" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness SourceStrict DecidedStrict) Par1))
type Rep (Either a b)
Instance details Defined in Data.Strict.Either type Rep (Either a b) = D1 (MetaData "Either" "Data.Strict.Either" "strict-0.4-DcORXBfkCIx3v5lLd1UYRe" False) (C1 (MetaCons "Left" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 a)) :+: C1 (MetaCons "Right" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 b)))

isRight :: Either a b -> Bool #

Yields True iff the argument is of the form Right _.

isLeft :: Either a b -> Bool #

Yields True iff the argument is of the form Left _.

either :: (a -> c) -> (b -> c) -> Either a b -> c #

Case analysis: if the value is Left a, apply the first function to a; if it is Right b, apply the second function to b.

lefts :: [Either a b] -> [a] #

Analogous to lefts in Data.Either.

rights :: [Either a b] -> [b] #

Analogous to rights in Data.Either.

partitionEithers :: [Either a b] -> ([a], [b]) #

Analogous to partitionEithers in Data.Either.

_Left :: Prism (Either a c) (Either b c) a b #

Analogous to _Left in Control.Lens.Prism.

_Right :: Prism (Either c a) (Either c b) a b #

Analogous to _Right in Control.Lens.Prism.