these-0.7.3: An either-or-both data type & a generalized 'zip with padding' typeclass

Safe Haskell None Haskell98

Data.These

Description

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

Synopsis

Documentation

data These a b Source #

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

 Source # MethodsliftToJSON2 :: (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 # Source # MethodsliftParseJSON2 :: (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] # Source # Methodsbimap :: (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 # Source # Methodsbitraverse :: Applicative f => (a -> f c) -> (b -> f d) -> These a b -> f (These c d) # Source # Methodsbifold :: 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 # Source # Methodsbitraverse1 :: 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) # Source # Methodsbifold1 :: Semigroup m => These m m -> m #bifoldMap1 :: Semigroup m => (a -> m) -> (b -> m) -> These a b -> m # Source # Methodsbicrosswalk :: Align f => (a -> f c) -> (b -> f d) -> These a b -> f (These c d) Source #bisequenceL :: Align f => These (f a) (f b) -> f (These a b) Source # Semigroup c => MonadChronicle c (These c) Source # Methodsdictate :: c -> These c () Source #disclose :: Default a => c -> These c a Source #confess :: c -> These c a Source #memento :: These c a -> These c (Either c a) Source #absolve :: a -> These c a -> These c a Source #condemn :: These c a -> These c a Source #retcon :: (c -> c) -> These c a -> These c a Source #chronicle :: These c a -> These c a Source # Semigroup a => Monad (These a) Source # Methods(>>=) :: These a a -> (a -> These a b) -> These a b #(>>) :: These a a -> These a b -> These a b #return :: a -> These a a #fail :: String -> These a a # Functor (These a) Source # Methodsfmap :: (a -> b) -> These a a -> These a b #(<\$) :: a -> These a b -> These a a # Semigroup a => Applicative (These a) Source # Methodspure :: a -> These a a #(<*>) :: These a (a -> b) -> These a a -> These a b #(*>) :: These a a -> These a b -> These a b #(<*) :: These a a -> These a b -> These a a # Source # Methodsfold :: Monoid m => These a m -> m #foldMap :: Monoid m => (a -> m) -> These a a -> m #foldr :: (a -> b -> b) -> b -> These a a -> b #foldr' :: (a -> b -> b) -> b -> These a a -> b #foldl :: (b -> a -> b) -> b -> These a a -> b #foldl' :: (b -> a -> b) -> b -> These a a -> b #foldr1 :: (a -> a -> a) -> These a a -> a #foldl1 :: (a -> a -> a) -> These a a -> a #toList :: These a a -> [a] #null :: These a a -> Bool #length :: These a a -> Int #elem :: Eq a => a -> These a a -> Bool #maximum :: Ord a => These a a -> a #minimum :: Ord a => These a a -> a #sum :: Num a => These a a -> a #product :: Num a => These a a -> a # Source # Methodstraverse :: Applicative f => (a -> f b) -> These a a -> f (These a b) #sequenceA :: Applicative f => These a (f a) -> f (These a a) #mapM :: Monad m => (a -> m b) -> These a a -> m (These a b) #sequence :: Monad m => These a (m a) -> m (These a a) # ToJSON a => ToJSON1 (These a) Source # MethodsliftToJSON :: (a -> Value) -> ([a] -> Value) -> These a a -> Value #liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [These a a] -> Value #liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> These a a -> Encoding #liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [These a a] -> Encoding # FromJSON a => FromJSON1 (These a) Source # MethodsliftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (These a a) #liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [These a a] # Semigroup a => Apply (These a) Source # Methods(<.>) :: These a (a -> b) -> These a a -> These a b #(.>) :: These a a -> These a b -> These a b #(<.) :: These a a -> These a b -> These a a # Semigroup a => Bind (These a) Source # Methods(>>-) :: These a a -> (a -> These a b) -> These a b #join :: These a (These a a) -> These a a # Source # Methodscrosswalk :: Align f => (a -> f b) -> These a a -> f (These a b) Source #sequenceL :: Align f => These a (f a) -> f (These a a) Source # (Eq b, Eq a) => Eq (These a b) Source # Methods(==) :: These a b -> These a b -> Bool #(/=) :: These a b -> These a b -> Bool # (Data b, Data a) => Data (These a b) Source # Methodsgfoldl :: (forall d c. Data d => c (d -> c) -> d -> c c) -> (forall g. g -> c g) -> These a b -> c (These a b) #gunfold :: (forall c r. Data c => c (c -> 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 c. Data c => c -> c) -> 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 b, Ord a) => Ord (These a b) Source # Methodscompare :: 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 b, Read a) => Read (These a b) Source # MethodsreadsPrec :: Int -> ReadS (These a b) #readList :: ReadS [These a b] #readPrec :: ReadPrec (These a b) #readListPrec :: ReadPrec [These a b] # (Show b, Show a) => Show (These a b) Source # MethodsshowsPrec :: Int -> These a b -> ShowS #show :: These a b -> String #showList :: [These a b] -> ShowS # Generic (These a b) Source # Associated Typestype Rep (These a b) :: * -> * # Methodsfrom :: 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) Source # Methods(<>) :: These a b -> These a b -> These a b #sconcat :: NonEmpty (These a b) -> These a b #stimes :: Integral b => b -> These a b -> These a b # (Function a, Function b) => Function (These a b) Source # Methodsfunction :: (These a b -> b) -> These a b :-> b # (Arbitrary a, Arbitrary b) => Arbitrary (These a b) Source # Methodsarbitrary :: Gen (These a b) #shrink :: These a b -> [These a b] # (CoArbitrary a, CoArbitrary b) => CoArbitrary (These a b) Source # Methodscoarbitrary :: These a b -> Gen b -> Gen b # (Hashable a, Hashable b) => Hashable (These a b) Source # MethodshashWithSalt :: Int -> These a b -> Int #hash :: These a b -> Int # (ToJSON a, ToJSON b) => ToJSON (These a b) Source # MethodstoJSON :: 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) Source # MethodsparseJSON :: Value -> Parser (These a b) #parseJSONList :: Value -> Parser [These a b] # (Binary a, Binary b) => Binary (These a b) Source # Methodsput :: These a b -> Put #get :: Get (These a b) #putList :: [These a b] -> Put # (NFData a, NFData b) => NFData (These a b) Source # Methodsrnf :: These a b -> () # type Rep (These a b) Source # type Rep (These a b) = D1 (MetaData "These" "Data.These" "these-0.7.3-GF3FiIvDV6m6eAZoaTsIto" False) ((:+:) (C1 (MetaCons "This" PrefixI False) (S1 (MetaSel (Nothing Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 a))) ((:+:) (C1 (MetaCons "That" PrefixI False) (S1 (MetaSel (Nothing Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 b))) (C1 (MetaCons "These" PrefixI False) ((:*:) (S1 (MetaSel (Nothing Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 a)) (S1 (MetaSel (Nothing Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 b))))))

Functions to get rid of These

these :: (a -> c) -> (b -> c) -> (a -> b -> c) -> These a b -> c Source #

Case analysis for the These type.

fromThese :: a -> b -> These a b -> (a, b) Source #

Takes two default values and produces a tuple.

mergeThese :: (a -> a -> a) -> These a a -> a Source #

Coalesce with the provided operation.

mergeTheseWith :: (a -> c) -> (b -> c) -> (c -> c -> c) -> These a b -> c Source #

BiMap and coalesce results with the provided operation.

Traversals

here :: Applicative f => (a -> f b) -> These a t -> f (These b t) Source #

A Traversal of the first half of a These, suitable for use with Control.Lens.

there :: Applicative f => (a -> f b) -> These t a -> f (These t b) Source #

A Traversal of the second half of a These, suitable for use with Control.Lens.

Prisms

_This :: (Choice p, Applicative f) => p a (f a) -> p (These a b) (f (These a b)) Source #

A Prism selecting the This constructor.

_That :: (Choice p, Applicative f) => p b (f b) -> p (These a b) (f (These a b)) Source #

A Prism selecting the That constructor.

_These :: (Choice p, Applicative f) => p (a, b) (f (a, b)) -> p (These a b) (f (These a b)) Source #

A Prism selecting the These constructor. These names are ridiculous!

Case selections

justThis :: These a b -> Maybe a Source #

justThis = preview _This

justThat :: These a b -> Maybe b Source #

justThat = preview _That

justThese :: These a b -> Maybe (a, b) Source #

justThese = preview _These

catThis :: [These a b] -> [a] Source #

Select all This constructors from a list.

catThat :: [These a b] -> [b] Source #

Select all That constructors from a list.

catThese :: [These a b] -> [(a, b)] Source #

Select all These constructors from a list.

partitionThese :: [These a b] -> ([(a, b)], ([a], [b])) Source #

Select each constructor and partition them into separate lists.

Case predicates

isThis :: These a b -> Bool Source #

isThis = isJust . justThis

isThat :: These a b -> Bool Source #

isThat = isJust . justThat

isThese :: These a b -> Bool Source #

isThese = isJust . justThese

Map operations

mapThese :: (a -> c) -> (b -> d) -> These a b -> These c d Source #

Bifunctor map.

mapThis :: (a -> c) -> These a b -> These c b Source #

mapThis = over here

mapThat :: (b -> d) -> These a b -> These a d Source #

mapThat = over there

For zipping and unzipping of structures with These values, see Data.Align.