Portability | Rank2Types |
---|---|
Stability | provisional |
Maintainer | Edward Kmett <ekmett@gmail.com> |
Safe Haskell | Safe-Infered |
- at :: Ord k => k -> SimpleIndexedLens k (Map k v) (Maybe v)
- traverseMap :: IndexedTraversal k (Map k v) (Map k v') v v'
- traverseAt :: Ord k => k -> SimpleIndexedTraversal k (Map k v) v
- traverseAtMin :: SimpleIndexedTraversal k (Map k v) v
- traverseAtMax :: SimpleIndexedTraversal k (Map k v) v
Documentation
at :: Ord k => k -> SimpleIndexedLens k (Map k v) (Maybe v)Source
This Lens
can be used to read, write or delete the value associated with a key in a Map
.
>>>
:m + Control.Lens Data.Map.Lens
>>>
Map.fromList [("hello",12)] ^.at "hello"
Just 12
>>>
at 10 .~ Just "hello" $ Map.empty
fromList [(10,"hello")]
at :: Ord k => k -> (Maybe v -> f (Maybe v)) -> Map k v -> f (Map k v)
traverseMap :: IndexedTraversal k (Map k v) (Map k v') v v'Source
Traversal of a Map
indexed by the key.
traverseAt :: Ord k => k -> SimpleIndexedTraversal k (Map k v) vSource
Traverse the value at a given key in a Map
traverseAt :: (Applicative f, Ord k) => k -> (v -> f v) -> Map k v -> f (Map k v) traverseAt k = valueAt k . traverse
traverseAtMin :: SimpleIndexedTraversal k (Map k v) vSource
Traverse the value at the minimum key in a Map.
The key of the minimum element is available as the index of the traversal.
traverseAtMax :: SimpleIndexedTraversal k (Map k v) vSource
Traverse the value at the maximum key in a Map.
The key of the maximum element is available as the index of the traversal.