Data.Map.Monoidal

This module provides a Map variant which uses the value's Monoid instance to accumulate conflicting entries when merging Maps.

While some functions mirroring those of Map are provided here for convenience, more specialized needs will likely want to use either the Newtype or Wrapped instances to manipulate the underlying Map.

Documentation

data MonoidalMap k a

A Map with monoidal accumulation

Instances

Ord k => TraverseMin k (MonoidalMap k)

Ord k => TraverseMax k (MonoidalMap k)

Ord k => TraversableWithIndex k (MonoidalMap k)

Ord k => FunctorWithIndex k (MonoidalMap k)

Ord k => FoldableWithIndex k (MonoidalMap k)

Functor (MonoidalMap k)

Foldable (MonoidalMap k)

Traversable (MonoidalMap k)

Ord k => IsList (MonoidalMap k a)

(Eq k, Eq a) => Eq (MonoidalMap k a)

(Data k, Data a, Ord k) => Data (MonoidalMap k a)

(Ord k, Ord a) => Ord (MonoidalMap k a)

(Ord k, Read k, Read a) => Read (MonoidalMap k a)

(Show k, Show a) => Show (MonoidalMap k a)

(Ord k, Monoid a) => Monoid (MonoidalMap k a)

(NFData k, NFData a) => NFData (MonoidalMap k a)

Wrapped (MonoidalMap k a)

AsEmpty (MonoidalMap k a)

Ord k => Ixed (MonoidalMap k a)

Ord k => At (MonoidalMap k a)

Typeable (* -> * -> *) MonoidalMap

Newtype (MonoidalMap k a) (Map k a)

Each (MonoidalMap k a) (MonoidalMap k b) a b

type Item (MonoidalMap k a) = (k, a)

type Unwrapped (MonoidalMap k a) = Map k a

type IxValue (MonoidalMap k a) = a

type Index (MonoidalMap k a) = k

Often-needed functions

singleton :: Ord k => k -> a -> MonoidalMap k a

O(1). A map with a single element.

size :: MonoidalMap k a -> Int

O(1). The number of elements in the map.

member :: Ord k => k -> MonoidalMap k a -> Bool

O(log n). Is the key a member of the map? See also notMember.

notMember :: Ord k => k -> MonoidalMap k a -> Bool

O(log n). Is the key not a member of the map? See also member.

findWithDefault :: Ord k => a -> k -> MonoidalMap k a -> a

O(log n). The expression (findWithDefault def k map) returns the value at key k or returns default value def when the key is not in the map.

elems :: MonoidalMap k a -> [a]

O(n). Return all elements of the map in the ascending order of their keys. Subject to list fusion.

keys :: MonoidalMap k a -> [k]

O(n). Return all keys of the map in ascending order. Subject to list fusion.