Module

Data.Bitraversable

#Bitraversable

class (Bifunctor t, Bifoldable t) <= Bitraversable t  where

Bitraversable represents data structures with two type arguments which can be traversed.

A traversal for such a structure requires two functions, one for each type argument. Type class instances should choose the appropriate function based on the type of the element encountered at each point of the traversal.

Default implementations are provided by the following functions:

  • bitraverseDefault
  • bisequenceDefault

Members

Instances

#bitraverseDefault

bitraverseDefault :: forall t f a b c d. Bitraversable t => Applicative f => (a -> f c) -> (b -> f d) -> t a b -> f (t c d)

A default implementation of bitraverse using bisequence and bimap.

#bisequenceDefault

bisequenceDefault :: forall t f a b. Bitraversable t => Applicative f => t (f a) (f b) -> f (t a b)

A default implementation of bisequence using bitraverse.

#ltraverse

ltraverse :: forall t b c a f. Bitraversable t => Applicative f => (a -> f c) -> t a b -> f (t c b)

#rtraverse

rtraverse :: forall t b c a f. Bitraversable t => Applicative f => (b -> f c) -> t a b -> f (t a c)

#bifor

bifor :: forall t f a b c d. Bitraversable t => Applicative f => t a b -> (a -> f c) -> (b -> f d) -> f (t c d)

Traverse a data structure, accumulating effects and results using an Applicative functor.

#lfor

lfor :: forall t b c a f. Bitraversable t => Applicative f => t a b -> (a -> f c) -> f (t c b)

#rfor

rfor :: forall t b c a f. Bitraversable t => Applicative f => t a b -> (b -> f c) -> f (t a c)

Re-exports from Data.Bifoldable

#Bifoldable

class Bifoldable p  where

Bifoldable represents data structures with two type arguments which can be folded.

A fold for such a structure requires two step functions, one for each type argument. Type class instances should choose the appropriate step function based on the type of the element encountered at each point of the fold.

Default implementations are provided by the following functions:

  • bifoldrDefault
  • bifoldlDefault
  • bifoldMapDefaultR
  • bifoldMapDefaultL

Note: some combinations of the default implementations are unsafe to use together - causing a non-terminating mutually recursive cycle. These combinations are documented per function.

Members

  • bifoldr :: forall a b c. (a -> c -> c) -> (b -> c -> c) -> c -> p a b -> c
  • bifoldl :: forall a b c. (c -> a -> c) -> (c -> b -> c) -> c -> p a b -> c
  • bifoldMap :: forall m a b. Monoid m => (a -> m) -> (b -> m) -> p a b -> m

Instances

#bitraverse_

bitraverse_ :: forall t f a b c d. Bifoldable t => Applicative f => (a -> f c) -> (b -> f d) -> t a b -> f Unit

Traverse a data structure, accumulating effects using an Applicative functor, ignoring the final result.

#bisequence_

bisequence_ :: forall t f a b. Bifoldable t => Applicative f => t (f a) (f b) -> f Unit

Collapse a data structure, collecting effects using an Applicative functor, ignoring the final result.

#bifor_

bifor_ :: forall t f a b c d. Bifoldable t => Applicative f => t a b -> (a -> f c) -> (b -> f d) -> f Unit

A version of bitraverse_ with the data structure as the first argument.

#bifoldrDefault

bifoldrDefault :: forall p a b c. Bifoldable p => (a -> c -> c) -> (b -> c -> c) -> c -> p a b -> c

A default implementation of bifoldr using bifoldMap.

Note: when defining a Bifoldable instance, this function is unsafe to use in combination with bifoldMapDefaultR.

#bifoldlDefault

bifoldlDefault :: forall p a b c. Bifoldable p => (c -> a -> c) -> (c -> b -> c) -> c -> p a b -> c

A default implementation of bifoldl using bifoldMap.

Note: when defining a Bifoldable instance, this function is unsafe to use in combination with bifoldMapDefaultL.

#bifoldMapDefaultR

bifoldMapDefaultR :: forall p m a b. Bifoldable p => Monoid m => (a -> m) -> (b -> m) -> p a b -> m

A default implementation of bifoldMap using bifoldr.

Note: when defining a Bifoldable instance, this function is unsafe to use in combination with bifoldrDefault.

#bifoldMapDefaultL

bifoldMapDefaultL :: forall p m a b. Bifoldable p => Monoid m => (a -> m) -> (b -> m) -> p a b -> m

A default implementation of bifoldMap using bifoldl.

Note: when defining a Bifoldable instance, this function is unsafe to use in combination with bifoldlDefault.

#bifold

bifold :: forall t m. Bifoldable t => Monoid m => t m m -> m

Fold a data structure, accumulating values in a monoidal type.

#biany

biany :: forall t a b c. Bifoldable t => BooleanAlgebra c => (a -> c) -> (b -> c) -> t a b -> c

Test whether a predicate holds at any position in a data structure.

#biall

biall :: forall t a b c. Bifoldable t => BooleanAlgebra c => (a -> c) -> (b -> c) -> t a b -> c

Test whether a predicate holds at all positions in a data structure.

Modules