Module

Data.Bifoldable

#Bifoldable 

class Bifoldable :: (Type -> Type -> Type) -> Constraintclass 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

#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.

#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.

#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.

#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.

#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