Safe Haskell	Safe
Language	Haskell2010

Data.Strict.Either

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
either :: (a -> c) -> (b -> c) -> Either a b -> c
isLeft :: Either a b -> Bool
isRight :: Either a b -> Bool
fromLeft :: Either a b -> a
fromRight :: Either a b -> b
lefts :: [Either a b] -> [a]
rights :: [Either a b] -> [b]
partitionEithers :: [Either a b] -> ([a], [b])

Documentation

data Either a b #

The strict choice type.

Constructors

Left !a
Right !b

Instances

Instances details

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 # 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 :: forall (a0 :: k). Either a a0 -> Rep1 (Either a) a0 # to1 :: forall (a0 :: k). 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 :: forall r r'. (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 #
(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 -> () #
(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 #
Strict (Either a b) (Either a b) #
Instance details Defined in Data.Strict.Classes Methods toStrict :: Either0 a b -> Either a b # toLazy :: Either a b -> Either0 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-0.4.0.1" '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-0.4.0.1" '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)))

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.

isLeft :: Either a b -> Bool #

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

isRight :: Either a b -> Bool #

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

fromLeft :: Either a b -> a #

Extracts the element out of a Left and throws an error if the argument is a Right.

fromRight :: Either a b -> b #

Extracts the element out of a Right and throws an error if the argument is a Left.

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.