Data.Diverse.Profunctor.Which

Combinators similar to Profunctor Choice

type Faceted a as x b bs y = (MatchingFacet a x y, AsFacet b y)

A friendlier constraint synonym for faceted.

faceted :: forall w a as x b bs y. (Choice w, Faceted a as x b bs y) => w a b -> w x y

Like Choice or ArrowChoice but lifting into a polymorphic variant.

facetedK :: forall m a as x b bs y. (Monad m, Faceted a as x b bs y) => (a -> m b) -> x -> m y

faceted under Kleisli

type Injected a2 a3 b2 b3 = (Reinterpret a2 a3, ChooseBoth (Complement a3 a2) b2 b3, Complement a2 a3 ~ '[])

A friendlier constraint synonym for injected.

injected :: forall w a2 a3 b2 b3. (Choice w, Injected a2 a3 b2 b3) => w (Which a2) (Which b2) -> w (Which a3) (Which b3)

Like Choice or ArrowChoice but lifting from Which into another type of Which NB. It is a compile error if all of the input types in the second arrow a is not the output types of the first arrow. This prevents surprising behaviour where the second arrow is completely ignored.

injectedK :: forall m a2 a3 b2 b3. (Monad m, Injected a2 a3 b2 b3) => (Which a2 -> m (Which b2)) -> Which a3 -> m (Which b3)

injected under Kleisli

type ChooseFrom a1 a2 a3 = (Reinterpret a2 a3, a1 ~ Complement a3 a2, a3 ~ Append a1 a2)

A friendlier constraint synonym for chooseFrom. Redundant constraint: a3 ~ Append a1 a2 is redundant but narrows down a3

type ChooseBoth b1 b2 b3 = (Diversify b1 b3, Diversify b2 b3, b3 ~ AppendUnique b1 b2)

A friendlier constraint synonym for chooseBoth. Redundant constraint: b3 ~ AppendUnique b1 b2 is redundant but narrows down b3

chooseBetween :: forall w a1 a2 a3 b1 b2 b3. (Category w, Choice w, ChooseFrom a1 a2 a3, ChooseBoth b1 b2 b3) => w (Which a1) (Which b1) -> w (Which a2) (Which b2) -> w (Which a3) (Which b3) infixr 2

Split the input between the two argument arrows, retagging and merging their outputs. The output is merged into a Which of unique types. Analogous to a Which combination of both +++ and |||. It is a compile error if the types are not distinct after Appending both argument arrows inputs. This is to prevent accidently processing an input type twice. The compile error will be due to (Append a1 a2) which will not satisfy UniqueMember constraints in Reinterpret.

chooseBetweenK :: forall m a1 a2 a3 b1 b2 b3. (Monad m, ChooseFrom a1 a2 a3, ChooseBoth b1 b2 b3) => (Which a1 -> m (Which b1)) -> (Which a2 -> m (Which b2)) -> Which a3 -> m (Which b3) infixr 2

chooseBetween under Kleisli

thenChoose :: forall w a a2 b1 b2 b3. (Category w, Choice w, Injected a2 b1 b2 b3) => w a (Which b1) -> w (Which a2) (Which b2) -> w a (Which b3) infixr 2

Left-to-right chaining of arrows one after another, where left over possibilities not handled by the right arrow is forwarded to the output. It is a compile error if the types are not distinct in each of the argument arrow inputs, or if the types are not distinct in each of the argument arrow output. NB. It is currently not a compile error if the input of the second arrow is distinct from the output of the first arrrow, in which case this function does not change anything except to add the types of the second arrow to the output.

thenChooseK :: forall m a a2 b1 b2 b3. (Monad m, Injected a2 b1 b2 b3) => (a -> m (Which b1)) -> (Which a2 -> m (Which b2)) -> a -> m (Which b3) infixr 2

thenChoose under Kleisli

also :: (Semigroup (f (Which a3)), Functor f, ChooseBoth a1 a2 a3) => f (Which a1) -> f (Which a2) -> f (Which a3) infixr 6

alternatively :: (Alternative f, ChooseBoth a1 a2 a3) => f (Which a1) -> f (Which a2) -> f (Which a3) infixl 3