these-1.1: An either-or-both data type.

Safe Haskell Trustworthy Haskell2010

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.

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

Constructors

 This a That b These a b
Instances
 Source # Instance detailsDefined in Data.These 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 # Since: 0.8 Instance detailsDefined in Data.These Methodsswap :: These a b -> These b a # Source # Since: 0.8 Instance detailsDefined in Data.These Methodsassoc :: These (These a b) c -> These a (These b c) #unassoc :: These a (These b c) -> These (These a b) c # Source # Instance detailsDefined in Data.These Methodsbitraverse :: Applicative f => (a -> f c) -> (b -> f d) -> These a b -> f (These c d) # Source # Instance detailsDefined in Data.These 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 # Semigroup a => Monad (These a) Source # Instance detailsDefined 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) Source # Instance detailsDefined in Data.These Methodsfmap :: (a0 -> b) -> These a a0 -> These a b #(<$) :: a0 -> These a b -> These a a0 # Semigroup a => Applicative (These a) Source # Instance detailsDefined in Data.These Methodspure :: 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 # Source # Instance detailsDefined in Data.These Methodsfold :: 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 # Source # Instance detailsDefined in Data.These Methodstraverse :: 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) # Generic1 (These a :: Type -> Type) Source # Instance detailsDefined in Data.These Associated Typestype Rep1 (These a) :: k -> Type # Methodsfrom1 :: These a a0 -> Rep1 (These a) a0 #to1 :: Rep1 (These a) a0 -> These a a0 # (Eq a, Eq b) => Eq (These a b) Source # Instance detailsDefined 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) Source # Instance detailsDefined in Data.These Methodsgfoldl :: (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) Source # Instance detailsDefined in Data.These 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 a, Read b) => Read (These a b) Source # Instance detailsDefined in Data.These MethodsreadsPrec :: 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) Source # Instance detailsDefined in Data.These MethodsshowsPrec :: Int -> These a b -> ShowS #show :: These a b -> String #showList :: [These a b] -> ShowS # Generic (These a b) Source # Instance detailsDefined in Data.These Associated Typestype Rep (These a b) :: Type -> Type # 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 # Instance detailsDefined 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 # (Binary a, Binary b) => Binary (These a b) Source # Since: 0.7.1 Instance detailsDefined in Data.These Methodsput :: These a b -> Put #get :: Get (These a b) #putList :: [These a b] -> Put # (NFData a, NFData b) => NFData (These a b) Source # Since: 0.7.1 Instance detailsDefined in Data.These Methodsrnf :: These a b -> () # (Hashable a, Hashable b) => Hashable (These a b) Source # Instance detailsDefined in Data.These MethodshashWithSalt :: Int -> These a b -> Int #hash :: These a b -> Int # type Rep1 (These a :: Type -> Type) Source # Instance detailsDefined in Data.These type Rep1 (These a :: Type -> Type) = D1 (MetaData "These" "Data.These" "these-1.1-KhhUzpJHd2O1lVb9LFDPRw" 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) Par1) :+: C1 (MetaCons "These" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 a) :*: S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) Par1))) type Rep (These a b) Source # Instance detailsDefined in Data.These type Rep (These a b) = D1 (MetaData "These" "Data.These" "these-1.1-KhhUzpJHd2O1lVb9LFDPRw" 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)))) # 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. # Partition partitionThese :: [These a b] -> ([a], [b], [(a, b)]) Source # Select each constructor and partition them into separate lists. partitionHereThere :: [These a b] -> ([a], [b]) Source # Select here and there elements and partition them into separate lists. Since: 0.8 partitionEithersNE :: NonEmpty (Either a b) -> These (NonEmpty a) (NonEmpty b) Source # Like partitionEithers but for NonEmpty types. • either all are Left • either all are Right • or there is both Left and Right stuff Note: this is not online algorithm. In the worst case it will traverse the whole list before deciding the result constructor. >>> partitionEithersNE$ Left 'x' :| [Right 'y']
These ('x' :| "") ('y' :| "")

>>> partitionEithersNE \$ Left 'x' :| map Left "yz"
This ('x' :| "yz")


Since: 1.0.1

# Distributivity

This distributivity combinators aren't isomorphisms!

distrThesePair :: These (a, b) c -> (These a c, These b c) Source #

undistrThesePair :: (These a c, These b c) -> These (a, b) c Source #

distrPairThese :: (These a b, c) -> These (a, c) (b, c) Source #

undistrPairThese :: These (a, c) (b, c) -> (These a b, c) Source #