Safe Haskell	None
Language	Haskell98

Data.These

Contents

Functions to get rid of These
Traversals
Prisms
Case selections
Case predicates
Map operations

Description

The These type and associated operations. Now enhanced with Control.Lens magic!

Synopsis

data These a b
- = This a
- | That b
- | These a b
these :: (a -> c) -> (b -> c) -> (a -> b -> c) -> These a b -> c
fromThese :: a -> b -> These a b -> (a, b)
mergeThese :: (a -> a -> a) -> These a a -> a
mergeTheseWith :: (a -> c) -> (b -> c) -> (c -> c -> c) -> These a b -> c
here :: Applicative f => (a -> f b) -> These a t -> f (These b t)
there :: Applicative f => (a -> f b) -> These t a -> f (These t b)
_This :: (Choice p, Applicative f) => p a (f a) -> p (These a b) (f (These a b))
_That :: (Choice p, Applicative f) => p b (f b) -> p (These a b) (f (These a b))
_These :: (Choice p, Applicative f) => p (a, b) (f (a, b)) -> p (These a b) (f (These a b))
justThis :: These a b -> Maybe a
justThat :: These a b -> Maybe b
justThese :: These a b -> Maybe (a, b)
catThis :: [These a b] -> [a]
catThat :: [These a b] -> [b]
catThese :: [These a b] -> [(a, b)]
partitionThese :: [These a b] -> ([(a, b)], ([a], [b]))
isThis :: These a b -> Bool
isThat :: These a b -> Bool
isThese :: These a b -> Bool
mapThese :: (a -> c) -> (b -> d) -> These a b -> These c d
mapThis :: (a -> c) -> These a b -> These c b
mapThat :: (b -> d) -> These a b -> These a d

Documentation

data These a b #

The These type represents values with two non-exclusive possibilities.

This can be useful to represent combinations of two values, where the combination is defined if either input is. Algebraically, the type These A B represents (A + B + AB), which doesn't factor easily into sums and products--a type like Either A (B, Maybe A) is unclear and awkward to use.

These has straightforward instances of Functor, Monad, &c., and behaves like a hybrid error/writer monad, as would be expected.

Constructors

This a
That b
These a b

Instances

Arbitrary2 These #
Instance details Defined in Data.These Methods liftArbitrary2 :: Gen a -> Gen b -> Gen (These a b) # liftShrink2 :: (a -> [a]) -> (b -> [b]) -> These a b -> [These a b] #
ToJSON2 These #
Instance details Defined in Data.These Methods liftToJSON2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> These a b -> Value # liftToJSONList2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [These a b] -> Value # liftToEncoding2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> These a b -> Encoding # liftToEncodingList2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [These a b] -> Encoding #
FromJSON2 These #
Instance details Defined in Data.These Methods liftParseJSON2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (These a b) # liftParseJSONList2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [These a b] #
Bitraversable These #
Instance details Defined in Data.These Methods bitraverse :: Applicative f => (a -> f c) -> (b -> f d) -> These a b -> f (These c d) #
Bifoldable These #
Instance details Defined in Data.These Methods bifold :: Monoid m => These m m -> m # bifoldMap :: Monoid m => (a -> m) -> (b -> m) -> These a b -> m # bifoldr :: (a -> c -> c) -> (b -> c -> c) -> c -> These a b -> c # bifoldl :: (c -> a -> c) -> (c -> b -> c) -> c -> These a b -> c #
Bifunctor These #
Instance details Defined in Data.These Methods bimap :: (a -> b) -> (c -> d) -> These a c -> These b d # first :: (a -> b) -> These a c -> These b c # second :: (b -> c) -> These a b -> These a c #
Bitraversable1 These #
Instance details Defined in Data.These Methods bitraverse1 :: Apply f => (a -> f b) -> (c -> f d) -> These a c -> f (These b d) # bisequence1 :: Apply f => These (f a) (f b) -> f (These a b) #
Bifoldable1 These #
Instance details Defined in Data.These Methods bifold1 :: Semigroup m => These m m -> m # bifoldMap1 :: Semigroup m => (a -> m) -> (b -> m) -> These a b -> m #
Bicrosswalk These #
Instance details Defined in Data.Align Methods bicrosswalk :: Align f => (a -> f c) -> (b -> f d) -> These a b -> f (These c d) # bisequenceL :: Align f => These (f a) (f b) -> f (These a b) #
Semigroup c => MonadChronicle c (These c) #
Instance details Defined in Control.Monad.Chronicle.Class Methods dictate :: c -> These c () # disclose :: Default a => c -> These c a # confess :: c -> These c a # memento :: These c a -> These c (Either c a) # absolve :: a -> These c a -> These c a # condemn :: These c a -> These c a # retcon :: (c -> c) -> These c a -> These c a # chronicle :: These c a -> These c a #
Semigroup a => Monad (These a) #
Instance details Defined in Data.These Methods (>>=) :: These a a0 -> (a0 -> These a b) -> These a b # (>>) :: These a a0 -> These a b -> These a b # return :: a0 -> These a a0 # fail :: String -> These a a0 #
Functor (These a) #
Instance details Defined in Data.These Methods fmap :: (a0 -> b) -> These a a0 -> These a b # (<$) :: a0 -> These a b -> These a a0 #
Semigroup a => Applicative (These a) #
Instance details Defined in Data.These Methods pure :: a0 -> These a a0 # (<>) :: These a (a0 -> b) -> These a a0 -> These a b # liftA2 :: (a0 -> b -> c) -> These a a0 -> These a b -> These a c # (>) :: These a a0 -> These a b -> These a b # (<*) :: These a a0 -> These a b -> These a a0 #
Foldable (These a) #
Instance details Defined in Data.These Methods fold :: Monoid m => These a m -> m # foldMap :: Monoid m => (a0 -> m) -> These a a0 -> m # foldr :: (a0 -> b -> b) -> b -> These a a0 -> b # foldr' :: (a0 -> b -> b) -> b -> These a a0 -> b # foldl :: (b -> a0 -> b) -> b -> These a a0 -> b # foldl' :: (b -> a0 -> b) -> b -> These a a0 -> b # foldr1 :: (a0 -> a0 -> a0) -> These a a0 -> a0 # foldl1 :: (a0 -> a0 -> a0) -> These a a0 -> a0 # toList :: These a a0 -> [a0] # null :: These a a0 -> Bool # length :: These a a0 -> Int # elem :: Eq a0 => a0 -> These a a0 -> Bool # maximum :: Ord a0 => These a a0 -> a0 # minimum :: Ord a0 => These a a0 -> a0 # sum :: Num a0 => These a a0 -> a0 # product :: Num a0 => These a a0 -> a0 #
Traversable (These a) #
Instance details Defined in Data.These Methods traverse :: Applicative f => (a0 -> f b) -> These a a0 -> f (These a b) # sequenceA :: Applicative f => These a (f a0) -> f (These a a0) # mapM :: Monad m => (a0 -> m b) -> These a a0 -> m (These a b) # sequence :: Monad m => These a (m a0) -> m (These a a0) #
Arbitrary a => Arbitrary1 (These a) #
Instance details Defined in Data.These Methods liftArbitrary :: Gen a0 -> Gen (These a a0) # liftShrink :: (a0 -> [a0]) -> These a a0 -> [These a a0] #
ToJSON a => ToJSON1 (These a) #
Instance details Defined in Data.These Methods liftToJSON :: (a0 -> Value) -> ([a0] -> Value) -> These a a0 -> Value # liftToJSONList :: (a0 -> Value) -> ([a0] -> Value) -> [These a a0] -> Value # liftToEncoding :: (a0 -> Encoding) -> ([a0] -> Encoding) -> These a a0 -> Encoding # liftToEncodingList :: (a0 -> Encoding) -> ([a0] -> Encoding) -> [These a a0] -> Encoding #
FromJSON a => FromJSON1 (These a) #
Instance details Defined in Data.These Methods liftParseJSON :: (Value -> Parser a0) -> (Value -> Parser [a0]) -> Value -> Parser (These a a0) # liftParseJSONList :: (Value -> Parser a0) -> (Value -> Parser [a0]) -> Value -> Parser [These a a0] #
Semigroup a => Apply (These a) #
Instance details Defined in Data.These Methods (<.>) :: These a (a0 -> b) -> These a a0 -> These a b # (.>) :: These a a0 -> These a b -> These a b # (<.) :: These a a0 -> These a b -> These a a0 # liftF2 :: (a0 -> b -> c) -> These a a0 -> These a b -> These a c #
Semigroup a => Bind (These a) #
Instance details Defined in Data.These Methods (>>-) :: These a a0 -> (a0 -> These a b) -> These a b # join :: These a (These a a0) -> These a a0 #
Crosswalk (These a) #
Instance details Defined in Data.Align Methods crosswalk :: Align f => (a0 -> f b) -> These a a0 -> f (These a b) # sequenceL :: Align f => These a (f a0) -> f (These a a0) #
(Eq a, Eq b) => Eq (These a b) #
Instance details Defined in Data.These Methods (==) :: These a b -> These a b -> Bool # (/=) :: These a b -> These a b -> Bool #
(Data a, Data b) => Data (These a b) #
Instance details Defined in Data.These Methods gfoldl :: (forall d b0. Data d => c (d -> b0) -> d -> c b0) -> (forall g. g -> c g) -> These a b -> c (These a b) # gunfold :: (forall b0 r. Data b0 => c (b0 -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (These a b) # toConstr :: These a b -> Constr # dataTypeOf :: These a b -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (These a b)) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (These a b)) # gmapT :: (forall b0. Data b0 => b0 -> b0) -> These a b -> These a b # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> These a b -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> These a b -> r # gmapQ :: (forall d. Data d => d -> u) -> These a b -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> These a b -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> These a b -> m (These a b) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> These a b -> m (These a b) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> These a b -> m (These a b) #
(Ord a, Ord b) => Ord (These a b) #
Instance details Defined in Data.These Methods compare :: These a b -> These a b -> Ordering # (<) :: These a b -> These a b -> Bool # (<=) :: These a b -> These a b -> Bool # (>) :: These a b -> These a b -> Bool # (>=) :: These a b -> These a b -> Bool # max :: These a b -> These a b -> These a b # min :: These a b -> These a b -> These a b #
(Read a, Read b) => Read (These a b) #
Instance details Defined in Data.These Methods readsPrec :: Int -> ReadS (These a b) # readList :: ReadS [These a b] # readPrec :: ReadPrec (These a b) # readListPrec :: ReadPrec [These a b] #
(Show a, Show b) => Show (These a b) #
Instance details Defined in Data.These Methods showsPrec :: Int -> These a b -> ShowS # show :: These a b -> String # showList :: [These a b] -> ShowS #
Generic (These a b) #
Instance details Defined in Data.These Associated Types type Rep (These a b) :: * -> * # Methods from :: These a b -> Rep (These a b) x # to :: Rep (These a b) x -> These a b #
(Semigroup a, Semigroup b) => Semigroup (These a b) #
Instance details Defined in Data.These Methods (<>) :: These a b -> These a b -> These a b # sconcat :: NonEmpty (These a b) -> These a b # stimes :: Integral b0 => b0 -> These a b -> These a b #
(Function a, Function b) => Function (These a b) #
Instance details Defined in Data.These Methods function :: (These a b -> b0) -> These a b :-> b0 #
(Arbitrary a, Arbitrary b) => Arbitrary (These a b) #
Instance details Defined in Data.These Methods arbitrary :: Gen (These a b) # shrink :: These a b -> [These a b] #
(CoArbitrary a, CoArbitrary b) => CoArbitrary (These a b) #
Instance details Defined in Data.These Methods coarbitrary :: These a b -> Gen b0 -> Gen b0 #
(Hashable a, Hashable b) => Hashable (These a b) #
Instance details Defined in Data.These Methods hashWithSalt :: Int -> These a b -> Int # hash :: These a b -> Int #
(ToJSON a, ToJSON b) => ToJSON (These a b) #
Instance details Defined in Data.These Methods toJSON :: These a b -> Value # toEncoding :: These a b -> Encoding # toJSONList :: [These a b] -> Value # toEncodingList :: [These a b] -> Encoding #
(FromJSON a, FromJSON b) => FromJSON (These a b) #
Instance details Defined in Data.These Methods parseJSON :: Value -> Parser (These a b) # parseJSONList :: Value -> Parser [These a b] #
(Binary a, Binary b) => Binary (These a b) #
Instance details Defined in Data.These Methods put :: These a b -> Put # get :: Get (These a b) # putList :: [These a b] -> Put #
(NFData a, NFData b) => NFData (These a b) #
Instance details Defined in Data.These Methods rnf :: These a b -> () #
type Rep (These a b) #
Instance details Defined in Data.These type Rep (These a b) = D1 (MetaData "These" "Data.These" "these-0.7.4-LCozlh8ymLIHKKeX7ZIQuV" False) (C1 (MetaCons "This" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 a)) :+: (C1 (MetaCons "That" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 b)) :+: C1 (MetaCons "These" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 a) :*: S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 b))))