Combinators

Alternation

alternate :: (Foldable f, Alternative g) => f a -> g a

Generalization over many common natural transformations, including:

• listToMaybe
• maybeToList
• toList

• either (const Nothing) Just

alternateMap :: (Foldable f, Alternative g) => (a -> b) -> f a -> g b

alternate extended with ability to map the wrapped value.

alternateMapM :: (Foldable f, Alternative g) => (a -> g b) -> f a -> g b

alternateMap extended with ability to do the mapping in the Alternative context.

Traversal

iforM :: (Monad m, Traversable f) => f a -> (Int -> a -> m b) -> m (f b)

Indexed version of forM.