map package:aeson -package:async -package:base -is:exact -package:array

Map a function over all values in the map.

Transform the keys and values of a KeyMap.

Map values and collect the Just results.

Map values and collect the Just results.

Map a function over all values in the map.

Same as fmap. Provided for the consistency with ToJSONKeyFunction.

An isomorphism holds when lifted into a functor. For example, if a list contains a bunch of a's which are each isomorphic to a b, the whole list of a's is isomorphic to a list of b's.

>>> ["1","2","3"] ^. mapping _Show :: [Int]
[1,2,3]

>>> ([1,2,3] :: [Int]) ^. from (mapping _Show)
["1","2","3"]

This also hold across different functors:

>>> let l = mapping @[] @Maybe _Show

>>> :t l
l :: (Read b, Show b) => Iso [String] (Maybe String) [b] (Maybe b)

>>> ["1","2","3"] & l %~ Just . sum
Just "6"

Metadata keys for block-device-mapping/*.

An abstract interface for maps from JSON keys to values.

A map from JSON key type Key to v.

Convert a HashMap to a KeyMap.

Convert a HashMap Textto a KeyMap.

Convert a Map to a KeyMap.

Convert a Map Textto a KeyMap.

Convert a KeyMap to a HashMap.

Convert a KeyMap to a HashMap Text.

Convert a KeyMap to a Map.

Convert a KeyMap to a Map Text.

Contravariant map, as ToJSONKeyFunction is a contravariant functor.