Data.Distributive

class (Functor f) <= Distributive f  where

Categorical dual of Traversable:

• distribute is the dual of sequence - it zips an arbitrary collection of containers.
• collect is the dual of traverse - it traverses an arbitrary collection of values.

Laws:

• distribute = collect identity
• distribute <<< distribute = identity
• collect f = distribute <<< map f
• map f = unwrap <<< collect (Identity <<< f)
• map distribute <<< collect f = unwrap <<< collect (Compose <<< f)

Members

• distribute :: forall g a. Functor g => g (f a) -> f (g a)
• collect :: forall g b a. Functor g => (a -> f b) -> g a -> f (g b)

Instances

• Distributive Identity
• Distributive (Function e)

distributeDefault :: forall g f a. Distributive f => Functor g => g (f a) -> f (g a)

A default implementation of distribute, based on collect.

collectDefault :: forall g f b a. Distributive f => Functor g => (a -> f b) -> g a -> f (g b)

A default implementation of collect, based on distribute.

cotraverse :: forall g f b a. Distributive f => Functor g => (g a -> b) -> g (f a) -> f b

Zip an arbitrary collection of containers and summarize the results