Data.Filterable

class (Functor f) <= Filterable f  where

Filterable represents data structures which can be partitioned/filtered.

• partitionMap - partition a data structure based on an either predicate.
• partition - partition a data structure based on boolean predicate.
• filterMap - map over a data structure and filter based on a maybe.
• filter - filter a data structure based on a boolean.

Laws:

• map f ≡ filterMap (Just <<< f)
• filter ≡ filterMap <<< maybeBool
• filterMap p ≡ filter (isJust <<< p)

Default implementations are provided by the following functions:

• partitionDefault
• partitionDefaultFilter
• partitionDefaultFilterMap
• filterDefault
• filterDefaultPartition
• filterDefaultPartitionMap

Members

• partitionMap :: forall r l a. (a -> Either l r) -> f a -> { left :: f l, right :: f r }
• partition :: forall a. (a -> Boolean) -> f a -> { no :: f a, yes :: f a }
• filterMap :: forall b a. (a -> Maybe b) -> f a -> f b
• filter :: forall a. (a -> Boolean) -> f a -> f a

Instances

• Filterable Array
• Filterable Maybe
• (Monoid m) => Filterable (Either m)
• Filterable List
• (Ord k) => Filterable (Map k)

eitherBool :: forall a. (a -> Boolean) -> a -> Either a a

Upgrade a boolean-style predicate to an either-style predicate mapping.

maybeBool :: forall a. (a -> Boolean) -> a -> Maybe a

Upgrade a boolean-style predicate to a maybe-style predicate mapping.

partitionDefault :: forall a f. Filterable f => (a -> Boolean) -> f a -> { no :: f a, yes :: f a }

A default implementation of partition using partitionMap.

partitionDefaultFilter :: forall a f. Filterable f => (a -> Boolean) -> f a -> { no :: f a, yes :: f a }

A default implementation of partition using filter. Note that this is almost certainly going to be suboptimal compared to direct implementations.

partitionDefaultFilterMap :: forall a f. Filterable f => (a -> Boolean) -> f a -> { no :: f a, yes :: f a }

A default implementation of partition using filterMap. Note that this is almost certainly going to be suboptimal compared to direct implementations.

filterDefault :: forall a f. Filterable f => (a -> Boolean) -> f a -> f a

A default implementation of filter using filterMap.

filterDefaultPartition :: forall a f. Filterable f => (a -> Boolean) -> f a -> f a

A default implementation of filter using partition.

filterDefaultPartitionMap :: forall a f. Filterable f => (a -> Boolean) -> f a -> f a

A default implementation of filter using partitionMap.

partitioned :: forall r l f. Filterable f => f (Either l r) -> { left :: f l, right :: f r }

filtered :: forall a f. Filterable f => f (Maybe a) -> f a

Filter out all the Nothing values.

cleared :: forall b a f. Filterable f => f a -> f b

Filter out all values.