dhall-1.42.0: A configuration language guaranteed to terminate

Safe Haskell | Safe-Inferred
Language | Haskell2010

Dhall.Map

Contents

- Type
- Construction
- Constructing unordered `Map`s
- Sorting
- Insertion
- Deletion/Update
- Query
- Combine
- Traversals
- Conversions

Description

`Map` type used to represent records and unions

Synopsis

- data Map k v
- empty :: Ord k => Map k v
- singleton :: k -> v -> Map k v
- fromList :: Ord k => [(k, v)] -> Map k v
- fromListWithKey :: Ord k => (k -> v -> v -> v) -> [(k, v)] -> Map k v
- fromMap :: Map k v -> Map k v
- unorderedSingleton :: k -> v -> Map k v
- unorderedFromList :: Ord k => [(k, v)] -> Map k v
- sort :: Map k v -> Map k v
- isSorted :: Eq k => Map k v -> Bool
- insert :: Ord k => k -> v -> Map k v -> Map k v
- insertWith :: Ord k => (v -> v -> v) -> k -> v -> Map k v -> Map k v
- delete :: Ord k => k -> Map k v -> Map k v
- filter :: Ord k => (a -> Bool) -> Map k a -> Map k a
- partition :: Ord k => (a -> Bool) -> Map k a -> (Map k a, Map k a)
- restrictKeys :: Ord k => Map k a -> Set k -> Map k a
- withoutKeys :: Ord k => Map k a -> Set k -> Map k a
- mapMaybe :: Ord k => (a -> Maybe b) -> Map k a -> Map k b
- lookup :: Ord k => k -> Map k v -> Maybe v
- member :: Ord k => k -> Map k v -> Bool
- uncons :: Ord k => Map k v -> Maybe (k, v, Map k v)
- size :: Map k v -> Int
- union :: Ord k => Map k v -> Map k v -> Map k v
- unionWith :: Ord k => (v -> v -> v) -> Map k v -> Map k v -> Map k v
- outerJoin :: Ord k => (a -> c) -> (b -> c) -> (k -> a -> b -> c) -> Map k a -> Map k b -> Map k c
- intersection :: Ord k => Map k a -> Map k b -> Map k a
- intersectionWith :: Ord k => (a -> b -> c) -> Map k a -> Map k b -> Map k c
- difference :: Ord k => Map k a -> Map k b -> Map k a
- mapWithKey :: (k -> a -> b) -> Map k a -> Map k b
- traverseWithKey :: Ord k => Applicative f => (k -> a -> f b) -> Map k a -> f (Map k b)
- unorderedTraverseWithKey :: Ord k => Applicative f => (k -> a -> f b) -> Map k a -> f (Map k b)
- unorderedTraverseWithKey_ :: Ord k => Applicative f => (k -> a -> f ()) -> Map k a -> f ()
- foldMapWithKey :: (Monoid m, Ord k) => (k -> a -> m) -> Map k a -> m
- toList :: Ord k => Map k v -> [(k, v)]
- toAscList :: Map k v -> [(k, v)]
- toMap :: Map k v -> Map k v
- keys :: Map k v -> [k]
- keysSet :: Map k v -> Set k
- elems :: Ord k => Map k v -> [v]

# Type

data Map k v #

A `Map` that remembers the original ordering of keys

This is primarily used so that formatting preserves field order

This is done primarily to avoid a dependency on `insert-ordered-containers` and also to improve performance

#### Instances

Instances details

(Lift k, Lift v) => Lift (Map k v :: Type) # |
Instance details Defined in Dhall.Map Methods lift :: Quote m => Map k v -> m Exp # liftTyped :: forall (m :: Type -> Type). Quote m => Map k v -> Code m (Map k v) #
Ord k => Foldable (Map k) # |
Instance details Defined in Dhall.Map Methods fold :: Monoid m => Map k m -> m foldMap :: Monoid m => (a -> m) -> Map k a -> m foldMap' :: Monoid m => (a -> m) -> Map k a -> m foldr :: (a -> b -> b) -> b -> Map k a -> b foldr' :: (a -> b -> b) -> b -> Map k a -> b foldl :: (b -> a -> b) -> b -> Map k a -> b foldl' :: (b -> a -> b) -> b -> Map k a -> b foldr1 :: (a -> a -> a) -> Map k a -> a foldl1 :: (a -> a -> a) -> Map k a -> a toList :: Map k a -> [a] null :: Map k a -> Bool length :: Map k a -> Int elem :: Eq a => a -> Map k a -> Bool maximum :: Ord a => Map k a -> a minimum :: Ord a => Map k a -> a sum :: Num a => Map k a -> a product :: Num a => Map k a -> a
Ord k => Traversable (Map k) # |
Instance details Defined in Dhall.Map Methods traverse :: Applicative f => (a -> f b) -> Map k a -> f (Map k b) sequenceA :: Applicative f => Map k (f a) -> f (Map k a) mapM :: Monad m => (a -> m b) -> Map k a -> m (Map k b) # sequence :: Monad m => Map k (m a) -> m (Map k a) #
Functor (Map k) # |
Instance details Defined in Dhall.Map Methods fmap :: (a -> b) -> Map k a -> Map k b # (<$) :: a -> Map k b -> Map k a #
(Data k, Data v, Ord k) => Data (Map k v) # |
Instance details Defined in Dhall.Map Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Map k v -> c (Map k v) # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Map k v) # toConstr :: Map k v -> Constr # dataTypeOf :: Map k v -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Map k v)) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Map k v)) # gmapT :: (forall b. Data b => b -> b) -> Map k v -> Map k v # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Map k v -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Map k v -> r # gmapQ :: (forall d. Data d => d -> u) -> Map k v -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Map k v -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Map k v -> m (Map k v) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Map k v -> m (Map k v) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Map k v -> m (Map k v) #
Ord k => Monoid (Map k v) # |
    \x -> x <> mempty == (x :: Map Int Int)
    \x -> mempty <> x == (x :: Map Int Int)
Instance details Defined in Dhall.Map Methods mempty :: Map k v # mappend :: Map k v -> Map k v -> Map k v # mconcat :: [Map k v] -> Map k v #
Ord k => Semigroup (Map k v) # |
    \x y z -> x <> (y <> z) == (x <> y) <> (z :: Map Int Int)
Instance details Defined in Dhall.Map Methods (<>) :: Map k v -> Map k v -> Map k v # sconcat :: NonEmpty (Map k v) -> Map k v # stimes :: Integral b => b -> Map k v -> Map k v #
Generic (Map k v) # |
Instance details Defined in Dhall.Map Associated Types type Rep (Map k v) :: Type -> Type # Methods from :: Map k v -> Rep (Map k v) x # to :: Rep (Map k v) x -> Map k v #
Ord k => IsList (Map k v) # |
Instance details Defined in Dhall.Map Associated Types type Item (Map k v) # Methods fromList :: [Item (Map k v)] -> Map k v # fromListN :: Int -> [Item (Map k v)] -> Map k v # toList :: Map k v -> [Item (Map k v)] #
(Show k, Show v, Ord k) => Show (Map k v) # |
Instance details Defined in Dhall.Map Methods showsPrec :: Int -> Map k v -> ShowS # show :: Map k v -> String # showList :: [Map k v] -> ShowS #
(NFData k, NFData v) => NFData (Map k v) # |
Instance details Defined in Dhall.Map Methods rnf :: Map k v -> ()
(Ord k, Eq v) => Eq (Map k v) # |
Instance details Defined in Dhall.Map Methods (==) :: Map k v -> Map k v -> Bool # (/=) :: Map k v -> Map k v -> Bool #
(Ord k, Ord v) => Ord (Map k v) # |
    >>> fromList [("A",1),("B",2)] < fromList [("B",1),("A",0)]
    True
Instance details Defined in Dhall.Map Methods compare :: Map k v -> Map k v -> Ordering # (<) :: Map k v -> Map k v -> Bool # (<=) :: Map k v -> Map k v -> Bool # (>) :: Map k v -> Map k v -> Bool # (>=) :: Map k v -> Map k v -> Bool # max :: Map k v -> Map k v -> Map k v # min :: Map k v -> Map k v -> Map k v #
type Rep (Map k v) # |
Instance details Defined in Dhall.Map type Rep (Map k v)
type Item (Map k v) # |
Instance details Defined in Dhall.Map type Item (Map k v) = (k, v)

# Construction

empty :: Ord k => Map k v #

Create an empty `Map`

singleton :: k -> v -> Map k v #

Create a `Map` from a single key-value pair

    >>> singleton "A" 1
    fromList [("A",1)]

fromList :: Ord k => [(k, v)] -> Map k v #

Create a `Map` from a list of key-value pairs

    >>> fromList [("B",1),("A",2)]  -- The map preserves order
    fromList [("B",1),("A",2)]
    >>> fromList [("A",1),("A",2)]  -- For duplicates, later values take precedence
    fromList [("A",2)]

Note that this handling of duplicates means that `fromList` is not a monoid homomorphism:

    >>> fromList [(1, True)] <> fromList [(1, False)]
    fromList [(1,True)]
    >>> fromList ([(1, True)] <> [(1, False)])
    fromList [(1,False)]

fromListWithKey :: Ord k => (k -> v -> v -> v) -> [(k, v)] -> Map k v #

Create a `Map` from a list of key-value pairs with a combining function.

    >>> fromListWithKey (\k v1 v2 -> k ++ v1 ++ v2) [("B","v1"),("A","v2"),("B","v3")]
    fromList [("B","Bv3v1"),("A","v2")]

fromMap :: Map k v -> Map k v #

Create a `Map` from a `Data.Map.`Map``

# Constructing unordered `Map`s

unorderedSingleton :: k -> v -> Map k v #

Create a `Map` from a single key-value pair.

Any further operations on this map will not retain the order of the keys.

    >>> unorderedSingleton "A" 1
    fromList [("A",1)]

unorderedFromList :: Ord k => [(k, v)] -> Map k v #

Create a `Map` from a list of key-value pairs

Any further operations on this map will not retain the order of the keys.

    >>> unorderedFromList []
    fromList []
    >>> unorderedFromList [("B",1),("A",2)]  -- The map /doesn't/ preserve order
    fromList [("A",2),("B",1)]
    >>> unorderedFromList [("A",1),("A",2)]  -- For duplicates, later values take precedence
    fromList [("A",2)]

# Sorting

sort :: Map k v -> Map k v #

Sort the keys of a `Map`, forgetting the original ordering

    sort (sort x) = sort x

    >>> sort (fromList [("B",1),("A",2)])
    fromList [("A",2),("B",1)]

isSorted :: Eq k => Map k v -> Bool #

Check if the keys of a `Map` are already sorted

    isSorted (sort m) = True

    >>> isSorted (fromList [("B",1),("A",2)])  -- Sortedness is based only on keys
    False
    >>> isSorted (fromList [("A",2),("B",1)])
    True

# Insertion

insert :: Ord k => k -> v -> Map k v -> Map k v #

Insert a key-value pair into a `Map`, overriding any previous value stored underneath the same key, if present

    insert = insertWith (\v _ -> v)

    >>> insert "C" 1 (fromList [("B",2),("A",3)])  -- Values are inserted on left
    fromList [("C",1),("B",2),("A",3)]
    >>> insert "C" 1 (fromList [("C",2),("A",3)])  -- New value takes precedence
    fromList [("C",1),("A",3)]

insertWith :: Ord k => (v -> v -> v) -> k -> v -> Map k v -> Map k v #

Insert a key-value pair into a `Map`, using the supplied function to combine the new value with any old value underneath the same key, if present

    >>> insertWith (+) "C" 1 (fromList [("B",2),("A",3)])  -- No collision
    fromList [("C",1),("B",2),("A",3)]
    >>> insertWith (+) "C" 1 (fromList [("C",2),("A",3)])  -- Collision
    fromList [("C",3),("A",3)]

# Deletion/Update

delete :: Ord k => k -> Map k v -> Map k v #

Delete a key from a `Map` if present, otherwise return the original `Map`

    >>> delete "B" (fromList [("C",1),("B",2),("A",3)])
    fromList [("C",1),("A",3)]
    >>> delete "D" (fromList [("C",1),("B",2),("A",3)])
    fromList [("C",1),("B",2),("A",3)]

filter :: Ord k => (a -> Bool) -> Map k a -> Map k a #

Keep all values that satisfy the given predicate

    >>> filter even (fromList [("C",3),("B",2),("A",1)])
    fromList [("B",2)]
    >>> filter odd (fromList [("C",3),("B",2),("A",1)])
    fromList [("C",3),("A",1)]

partition :: Ord k => (a -> Bool) -> Map k a -> (Map k a, Map k a) #

Split the map into values that do and don't satisfy the predicate

    >>> partition even (fromList [("C",3),("B",2),("A",1)])
    (fromList [("B",2)],fromList [("C",3),("A",1)])
    >>> partition odd (fromList [("C",3),("B",2),("A",1)])
    (fromList [("C",3),("A",1)],fromList [("B",2)])

restrictKeys :: Ord k => Map k a -> Set k -> Map k a #

Restrict a `Map` to only those keys found in a `Data.Set.`Set``.

    >>> restrictKeys (fromList [("A",1),("B",2)]) (Data.Set.fromList ["A"])
    fromList [("A",1)]

withoutKeys :: Ord k => Map k a -> Set k -> Map k a #

Remove all keys in a `Data.Set.`Set`` from a `Map`

    >>> withoutKeys (fromList [("A",1),("B",2)]) (Data.Set.fromList ["A"])
    fromList [("B",2)]

mapMaybe :: Ord k => (a -> Maybe b) -> Map k a -> Map k b #

Transform all values in a `Map` using the supplied function, deleting the key if the function returns `Nothing`

    >>> mapMaybe Data.Maybe.listToMaybe (fromList [("C",[1]),("B",[]),("A",[3])])
    fromList [("C",1),("A",3)]

# Query

lookup :: Ord k => k -> Map k v -> Maybe v #

Retrieve a key from a `Map`

    lookup k mempty = empty

    lookup k (x <> y) = lookup k y <|> lookup k x

    >>> lookup "A" (fromList [("B",1),("A",2)])
    Just 2
    >>> lookup "C" (fromList [("B",1),("A",2)])
    Nothing

member :: Ord k => k -> Map k v -> Bool #

Check if a key belongs to a `Map`

    member k mempty = False

    member k (x <> y) = member k x || member k y

    >>> member "A" (fromList [("B",1),("A",2)])
    True
    >>> member "C" (fromList [("B",1),("A",2)])
    False

uncons :: Ord k => Map k v -> Maybe (k, v, Map k v) #

Retrieve the first key, value of the `Map`, if present, and also returning the rest of the `Map`.

    uncons mempty = empty

    uncons (singleton k v) = (k, v, mempty)

    >>> uncons (fromList [("C",1),("B",2),("A",3)])
    Just ("C",1,fromList [("B",2),("A",3)])
    >>> uncons (fromList [])
    Nothing

size :: Map k v -> Int #

    >>> size (fromList [("A",1)])
    1

# Combine

union :: Ord k => Map k v -> Map k v -> Map k v #

Combine two `Map`s, preferring keys from the first `Map`

    union = unionWith (\v _ -> v)

    >>> union (fromList [("D",1),("C",2)]) (fromList [("B",3),("A",4)])
    fromList [("D",1),("C",2),("B",3),("A",4)]
    >>> union (fromList [("D",1),("C",2)]) (fromList [("C",3),("A",4)])
    fromList [("D",1),("C",2),("A",4)]

unionWith :: Ord k => (v -> v -> v) -> Map k v -> Map k v -> Map k v #

Combine two `Map`s using a combining function for colliding keys

    >>> unionWith (+) (fromList [("D",1),("C",2)]) (fromList [("B",3),("A",4)])
    fromList [("D",1),("C",2),("B",3),("A",4)]
    >>> unionWith (+) (fromList [("D",1),("C",2)]) (fromList [("C",3),("A",4)])
    fromList [("D",1),("C",5),("A",4)]

outerJoin :: Ord k => (a -> c) -> (b -> c) -> (k -> a -> b -> c) -> Map k a -> Map k b -> Map k c #

A generalised `unionWith`.

    >>> outerJoin Left Left (\k a b -> Right (k, a, b)) (fromList [("A",1),("B",2)]) (singleton "A" 3)
    fromList [("A",Right ("A",1,3)),("B",Left 2)]

This function is much inspired by the Data.Semialign.Semialign class.

intersection :: Ord k => Map k a -> Map k b -> Map k a #

Combine two `Map` on their shared keys, keeping the value from the first `Map`

    intersection = intersectionWith (\v _ -> v)

    >>> intersection (fromList [("C",1),("B",2)]) (fromList [("B",3),("A",4)])
    fromList [("B",2)]

intersectionWith :: Ord k => (a -> b -> c) -> Map k a -> Map k b -> Map k c #

Combine two `Map`s on their shared keys, using the supplied function to combine values from the first and second `Map`

    >>> intersectionWith (+) (fromList [("C",1),("B",2)]) (fromList [("B",3),("A",4)])
    fromList [("B",5)]

difference :: Ord k => Map k a -> Map k b -> Map k a #

Compute the difference of two `Map`s by subtracting all keys from the second `Map` from the first `Map`

    >>> difference (fromList [("C",1),("B",2)]) (fromList [("B",3),("A",4)])
    fromList [("C",1)]

# Traversals

mapWithKey :: (k -> a -> b) -> Map k a -> Map k b #

Transform the values of a `Map` using their corresponding key

    mapWithKey (pure id) = id

    mapWithKey (liftA2 (.) f g) = mapWithKey f . mapWithKey g

    mapWithKey f mempty = mempty

    mapWithKey f (x <> y) = mapWithKey f x <> mapWithKey f y

    >>> mapWithKey (,) (fromList [("B",1),("A",2)])
    fromList [("B",("B",1)),("A",("A",2))]

traverseWithKey :: Ord k => Applicative f => (k -> a -> f b) -> Map k a -> f (Map k b) #

Traverse all of the key-value pairs in a `Map`, in their original order

    >>> traverseWithKey (,) (fromList [("B",1),("A",2)])
    ("BA",fromList [("B",1),("A",2)])

unorderedTraverseWithKey :: Ord k => Applicative f => (k -> a -> f b) -> Map k a -> f (Map k b) #

Same as `traverseWithKey`, except that the order of effects is not necessarily the same as the order of the keys

unorderedTraverseWithKey_ :: Ord k => Applicative f => (k -> a -> f ()) -> Map k a -> f () #

Traverse all of the key-value pairs in a `Map`, not preserving their original order, where the result of the computation can be forgotten.

Note that this is a strict traversal, fully traversing the map even when the Applicative is lazy in the remaining elements.

foldMapWithKey :: (Monoid m, Ord k) => (k -> a -> m) -> Map k a -> m #

Fold all of the key-value pairs in a `Map`, in their original order

    >>> foldMapWithKey (,) (fromList [("B",[1]),("A",[2])])
    ("BA",[1,2])

# Conversions

toList :: Ord k => Map k v -> [(k, v)] #

Convert a `Map` to a list of key-value pairs in the original order of keys

    >>> toList (fromList [("B",1),("A",2)])
    [("B",1),("A",2)]

toAscList :: Map k v -> [(k, v)] #

Convert a `Map` to a list of key-value pairs in ascending order of keys

toMap :: Map k v -> Map k v #

Convert a `Dhall.Map.`Map`` to a `Data.Map.`Map``

    >>> toMap (fromList [("B",1),("A",2)]) -- Order is lost upon conversion
    fromList [("A",2),("B",1)]

keys :: Map k v -> [k] #

Return the keys from a `Map` in their original order

    >>> keys (fromList [("B",1),("A",2)])
    ["B","A"]

keysSet :: Map k v -> Set k #

Return the `Data.Set.`Set`` of the keys

    >>> keysSet (fromList [("B",1),("A",2)])
    fromList ["A","B"]

elems :: Ord k => Map k v -> [v] #

Return the values from a `Map` in their original order.

    >>> elems (fromList [("B",1),("A",2)])
    [1,2]