Data.Semigroup.Foldable

class (Foldable t) <= Foldable1 t  where

Foldable1 represents data structures with a minimum of one element that can be folded.

• fold1 folds a structure using a Semigroup instance
• foldMap1 folds a structure by accumulating values in a Semigroup

Default implementations are provided by the following functions:

• fold1Default
• foldMap1Default

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

• foldMap1 :: forall m a. Semigroup m => (a -> m) -> t a -> m
• fold1 :: forall m. Semigroup m => t m -> m

Instances

• Foldable1 Dual
• Foldable1 Multiplicative

fold1Default :: forall m t. Foldable1 t => Semigroup m => t m -> m

A default implementation of fold1 using foldMap1.

foldMap1Default :: forall a m t. Foldable1 t => Functor t => Semigroup m => (a -> m) -> t a -> m

A default implementation of foldMap1 using fold1.

traverse1_ :: forall b a f t. Foldable1 t => Apply f => (a -> f b) -> t a -> f Unit

Traverse a data structure, performing some effects encoded by an Apply instance at each value, ignoring the final result.

for1_ :: forall b a f t. Foldable1 t => Apply f => t a -> (a -> f b) -> f Unit

A version of traverse1_ with its arguments flipped.

This can be useful when running an action written using do notation for every element in a data structure:

sequence1_ :: forall a f t. Foldable1 t => Apply f => t (f a) -> f Unit

Perform all of the effects in some data structure in the order given by the Foldable1 instance, ignoring the final result.