Safe Haskell	Safe
Language	Haskell2010

Data.These

Contents

Functions to get rid of These
Partition
Distributivity

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
partitionThese :: [ These a b] -> ([a], [b], [(a, b)])
partitionHereThere :: [ These a b] -> ([a], [b])
partitionEithersNE :: NonEmpty ( Either a b) -> These ( NonEmpty a) ( NonEmpty b)
distrThesePair :: These (a, b) c -> ( These a c, These b c)
undistrThesePair :: ( These a c, These b c) -> These (a, b) c
distrPairThese :: ( These a b, c) -> These (a, c) (b, c)
undistrPairThese :: These (a, c) (b, c) -> ( These a b, c)

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

Instances details

Bifunctor These Source #
Instance details Defined in Data.These Methods bimap :: (a -> b) -> (c -> d) -> These a c -> These b d Source # first :: (a -> b) -> These a c -> These b c Source # second :: (b -> c) -> These a b -> These a c Source #
Swap These Source #	Since: 0.8
Instance details Defined in Data.These Methods swap :: These a b -> These b a Source #
Assoc These Source #	Since: 0.8
Instance details Defined in Data.These Methods assoc :: These ( These a b) c -> These a ( These b c) Source # unassoc :: These a ( These b c) -> These ( These a b) c Source #
Bitraversable These Source #
Instance details Defined in Data.These Methods bitraverse :: Applicative f => (a -> f c) -> (b -> f d) -> These a b -> f ( These c d) Source #
Bifoldable These Source #
Instance details Defined in Data.These Methods bifold :: Monoid m => These m m -> m Source # bifoldMap :: Monoid m => (a -> m) -> (b -> m) -> These a b -> m Source # bifoldr :: (a -> c -> c) -> (b -> c -> c) -> c -> These a b -> c Source # bifoldl :: (c -> a -> c) -> (c -> b -> c) -> c -> These a b -> c Source #
Eq2 These Source #	Since: 1.1.1
Instance details Defined in Data.These Methods liftEq2 :: (a -> b -> Bool ) -> (c -> d -> Bool ) -> These a c -> These b d -> Bool Source #
Ord2 These Source #	Since: 1.1.1
Instance details Defined in Data.These Methods liftCompare2 :: (a -> b -> Ordering ) -> (c -> d -> Ordering ) -> These a c -> These b d -> Ordering Source #
Read2 These Source #	Since: 1.1.1
Instance details Defined in Data.These Methods liftReadsPrec2 :: ( Int -> ReadS a) -> ReadS [a] -> ( Int -> ReadS b) -> ReadS [b] -> Int -> ReadS ( These a b) Source # liftReadList2 :: ( Int -> ReadS a) -> ReadS [a] -> ( Int -> ReadS b) -> ReadS [b] -> ReadS [ These a b] Source # liftReadPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec ( These a b) Source # liftReadListPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec [ These a b] Source #
Show2 These Source #	Since: 1.1.1
Instance details Defined in Data.These Methods liftShowsPrec2 :: ( Int -> a -> ShowS ) -> ([a] -> ShowS ) -> ( Int -> b -> ShowS ) -> ([b] -> ShowS ) -> Int -> These a b -> ShowS Source # liftShowList2 :: ( Int -> a -> ShowS ) -> ([a] -> ShowS ) -> ( Int -> b -> ShowS ) -> ([b] -> ShowS ) -> [ These a b] -> ShowS Source #
NFData2 These Source #	Since: 1.1.1
Instance details Defined in Data.These Methods liftRnf2 :: (a -> ()) -> (b -> ()) -> These a b -> () Source #
Hashable2 These Source #	Since: 1.1.1
Instance details Defined in Data.These Methods liftHashWithSalt2 :: ( Int -> a -> Int ) -> ( Int -> b -> Int ) -> Int -> These a b -> Int Source #
Semigroup a => Monad ( These a) Source #
Instance details Defined in Data.These Methods (>>=) :: These a a0 -> (a0 -> These a b) -> These a b Source # (>>) :: These a a0 -> These a b -> These a b Source # return :: a0 -> These a a0 Source #
Functor ( These a) Source #
Instance details Defined in Data.These Methods fmap :: (a0 -> b) -> These a a0 -> These a b Source # (<$) :: a0 -> These a b -> These a a0 Source #
Semigroup a => Applicative ( These a) Source #
Instance details Defined in Data.These Methods pure :: a0 -> These a a0 Source # (<>) :: These a (a0 -> b) -> These a a0 -> These a b Source # liftA2 :: (a0 -> b -> c) -> These a a0 -> These a b -> These a c Source # (>) :: These a a0 -> These a b -> These a b Source # (<*) :: These a a0 -> These a b -> These a a0 Source #
Foldable ( These a) Source #
Instance details Defined in Data.These Methods fold :: Monoid m => These a m -> m Source # foldMap :: Monoid m => (a0 -> m) -> These a a0 -> m Source # foldMap' :: Monoid m => (a0 -> m) -> These a a0 -> m Source # foldr :: (a0 -> b -> b) -> b -> These a a0 -> b Source # foldr' :: (a0 -> b -> b) -> b -> These a a0 -> b Source # foldl :: (b -> a0 -> b) -> b -> These a a0 -> b Source # foldl' :: (b -> a0 -> b) -> b -> These a a0 -> b Source # foldr1 :: (a0 -> a0 -> a0) -> These a a0 -> a0 Source # foldl1 :: (a0 -> a0 -> a0) -> These a a0 -> a0 Source # toList :: These a a0 -> [a0] Source # null :: These a a0 -> Bool Source # length :: These a a0 -> Int Source # elem :: Eq a0 => a0 -> These a a0 -> Bool Source # maximum :: Ord a0 => These a a0 -> a0 Source # minimum :: Ord a0 => These a a0 -> a0 Source # sum :: Num a0 => These a a0 -> a0 Source # product :: Num a0 => These a a0 -> a0 Source #
Traversable ( These a) Source #
Instance details Defined in Data.These Methods traverse :: Applicative f => (a0 -> f b) -> These a a0 -> f ( These a b) Source # sequenceA :: Applicative f => These a (f a0) -> f ( These a a0) Source # mapM :: Monad m => (a0 -> m b) -> These a a0 -> m ( These a b) Source # sequence :: Monad m => These a (m a0) -> m ( These a a0) Source #
Eq a => Eq1 ( These a) Source #	Since: 1.1.1
Instance details Defined in Data.These Methods liftEq :: (a0 -> b -> Bool ) -> These a a0 -> These a b -> Bool Source #
Ord a => Ord1 ( These a) Source #	Since: 1.1.1
Instance details Defined in Data.These Methods liftCompare :: (a0 -> b -> Ordering ) -> These a a0 -> These a b -> Ordering Source #
Read a => Read1 ( These a) Source #	Since: 1.1.1
Instance details Defined in Data.These Methods liftReadsPrec :: ( Int -> ReadS a0) -> ReadS [a0] -> Int -> ReadS ( These a a0) Source # liftReadList :: ( Int -> ReadS a0) -> ReadS [a0] -> ReadS [ These a a0] Source # liftReadPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec ( These a a0) Source # liftReadListPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec [ These a a0] Source #
Show a => Show1 ( These a) Source #	Since: 1.1.1
Instance details Defined in Data.These Methods liftShowsPrec :: ( Int -> a0 -> ShowS ) -> ([a0] -> ShowS ) -> Int -> These a a0 -> ShowS Source # liftShowList :: ( Int -> a0 -> ShowS ) -> ([a0] -> ShowS ) -> [ These a a0] -> ShowS Source #
NFData a => NFData1 ( These a) Source #	Since: 1.1.1
Instance details Defined in Data.These Methods liftRnf :: (a0 -> ()) -> These a a0 -> () Source #
Hashable a => Hashable1 ( These a) Source #	Since: 1.1.1
Instance details Defined in Data.These Methods liftHashWithSalt :: ( Int -> a0 -> Int ) -> Int -> These a a0 -> Int Source #
Generic1 ( These a :: Type -> Type ) Source #
Instance details Defined in Data.These Associated Types type Rep1 ( These a) :: k -> Type Source # Methods from1 :: forall (a0 :: k). These a a0 -> Rep1 ( These a) a0 Source # to1 :: forall (a0 :: k). Rep1 ( These a) a0 -> These a a0 Source #
( Eq a, Eq b) => Eq ( These a b) Source #
Instance details Defined in Data.These Methods (==) :: These a b -> These a b -> Bool Source # (/=) :: These a b -> These a b -> Bool Source #
( Data a, Data b) => Data ( These a b) Source #
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) Source # gunfold :: ( forall b0 r. Data b0 => c (b0 -> r) -> c r) -> ( forall r. r -> c r) -> Constr -> c ( These a b) Source # toConstr :: These a b -> Constr Source # dataTypeOf :: These a b -> DataType Source # dataCast1 :: Typeable t => ( forall d. Data d => c (t d)) -> Maybe (c ( These a b)) Source # dataCast2 :: Typeable t => ( forall d e. ( Data d, Data e) => c (t d e)) -> Maybe (c ( These a b)) Source # gmapT :: ( forall b0. Data b0 => b0 -> b0) -> These a b -> These a b Source # gmapQl :: (r -> r' -> r) -> r -> ( forall d. Data d => d -> r') -> These a b -> r Source # gmapQr :: forall r r'. (r' -> r -> r) -> r -> ( forall d. Data d => d -> r') -> These a b -> r Source # gmapQ :: ( forall d. Data d => d -> u) -> These a b -> [u] Source # gmapQi :: Int -> ( forall d. Data d => d -> u) -> These a b -> u Source # gmapM :: Monad m => ( forall d. Data d => d -> m d) -> These a b -> m ( These a b) Source # gmapMp :: MonadPlus m => ( forall d. Data d => d -> m d) -> These a b -> m ( These a b) Source # gmapMo :: MonadPlus m => ( forall d. Data d => d -> m d) -> These a b -> m ( These a b) Source #
( Ord a, Ord b) => Ord ( These a b) Source #
Instance details Defined in Data.These Methods compare :: These a b -> These a b -> Ordering Source # (<) :: These a b -> These a b -> Bool Source # (<=) :: These a b -> These a b -> Bool Source # (>) :: These a b -> These a b -> Bool Source # (>=) :: These a b -> These a b -> Bool Source # max :: These a b -> These a b -> These a b Source # min :: These a b -> These a b -> These a b Source #
( Read a, Read b) => Read ( These a b) Source #
Instance details Defined in Data.These Methods readsPrec :: Int -> ReadS ( These a b) Source # readList :: ReadS [ These a b] Source # readPrec :: ReadPrec ( These a b) Source # readListPrec :: ReadPrec [ These a b] Source #
( Show a, Show b) => Show ( These a b) Source #
Instance details Defined in Data.These Methods showsPrec :: Int -> These a b -> ShowS Source # show :: These a b -> String Source # showList :: [ These a b] -> ShowS Source #
Generic ( These a b) Source #
Instance details Defined in Data.These Associated Types type Rep ( These a b) :: Type -> Type Source # Methods from :: These a b -> Rep ( These a b) x Source # to :: Rep ( These a b) x -> These a b Source #
( Semigroup a, Semigroup b) => Semigroup ( These a b) Source #
Instance details Defined in Data.These Methods (<>) :: These a b -> These a b -> These a b Source # sconcat :: NonEmpty ( These a b) -> These a b Source # stimes :: Integral b0 => b0 -> These a b -> These a b Source #
( Binary a, Binary b) => Binary ( These a b) Source #	Since: 0.7.1
Instance details Defined in Data.These Methods put :: These a b -> Put Source # get :: Get ( These a b) Source # putList :: [ These a b] -> Put Source #
( NFData a, NFData b) => NFData ( These a b) Source #	Since: 0.7.1
Instance details Defined in Data.These Methods rnf :: These a b -> () Source #
( Hashable a, Hashable b) => Hashable ( These a b) Source #
Instance details Defined in Data.These Methods hashWithSalt :: Int -> These a b -> Int Source # hash :: These a b -> Int Source #
type Rep1 ( These a :: Type -> Type ) Source #
Instance details Defined in Data.These type Rep1 ( These a :: Type -> Type ) = D1 (' MetaData "These" "Data.These" "these-1.1.1.1-GeR95OLAr5rCXHhUN7z1Qo" ' 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 details Defined in Data.These type Rep ( These a b) = D1 (' MetaData "These" "Data.These" "these-1.1.1.1-GeR95OLAr5rCXHhUN7z1Qo" ' 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 #

Documentation

Instances

Functions to get rid of These

Partition

Distributivity

Functions to get rid of `These`