Core.Data.Structures

Convenience wrappers around dictionary and collection types and tools facilitating conversion between them and various map and set types in common use in the Haskell ecosystem.

Map type

data Map κ ν

A mapping from keys to values.

The keys in a map needs to be an instance of the Key typeclass. Instances are already provided for many common element types.

Map implements Foldable, Monoid, etc so many common operations such as foldr to reduce the structure with a right fold, length to get the number of key/value pairs in the dictionary, null to test whether the map is empty, and (<>) to join two maps together are available.

To convert to other dictionary types see fromMap below.

(this is a thin wrapper around unordered-containers's HashMap, but if you use the conversion functions to extract the key/value pairs in a list the list will be ordered according to the keys' Ord instance)

Instances

Bifoldable Map

Defined in Core.Data.Structures

Methods

bifold :: Monoid m => Map m m -> m

bifoldMap :: Monoid m => (a -> m) -> (b -> m) -> Map a b -> m

bifoldr :: (a -> c -> c) -> (b -> c -> c) -> c -> Map a b -> c

bifoldl :: (c -> a -> c) -> (c -> b -> c) -> c -> Map a b -> c

Foldable (Map κ)

Defined in Core.Data.Structures

Methods

fold :: Monoid m => Map κ m -> m

foldMap :: Monoid m => (a -> m) -> Map κ a -> m

foldMap' :: Monoid m => (a -> m) -> Map κ a -> m

foldr :: (a -> b -> b) -> b -> Map κ a -> b

foldr' :: (a -> b -> b) -> b -> Map κ a -> b

foldl :: (b -> a -> b) -> b -> Map κ a -> b

foldl' :: (b -> a -> b) -> b -> Map κ a -> b

foldr1 :: (a -> a -> a) -> Map κ a -> a

foldl1 :: (a -> a -> a) -> Map κ a -> a

toList :: Map κ a -> [a]

null :: Map κ a -> Bool

length :: Map κ a -> Int

elem :: Eq a => a -> Map κ a -> Bool

maximum :: Ord a => Map κ a -> a

minimum :: Ord a => Map κ a -> a

sum :: Num a => Map κ a -> a

product :: Num a => Map κ a -> a

Key κ => IsList (Map κ ν)

Defined in Core.Data.Structures

Associated Types

type Item (Map κ ν)

Methods

fromList :: [Item (Map κ ν)] -> Map κ ν

fromListN :: Int -> [Item (Map κ ν)] -> Map κ ν

toList :: Map κ ν -> [Item (Map κ ν)]

(Eq κ, Eq ν) => Eq (Map κ ν)

Defined in Core.Data.Structures

Methods

(==) :: Map κ ν -> Map κ ν -> Bool

(/=) :: Map κ ν -> Map κ ν -> Bool

(Show κ, Show ν) => Show (Map κ ν)

Defined in Core.Data.Structures

Methods

showsPrec :: Int -> Map κ ν -> ShowS

show :: Map κ ν -> String

showList :: [Map κ ν] -> ShowS

Key κ => Semigroup (Map κ ν)

Defined in Core.Data.Structures

Methods

(<>) :: Map κ ν -> Map κ ν -> Map κ ν

sconcat :: NonEmpty (Map κ ν) -> Map κ ν

stimes :: Integral b => b -> Map κ ν -> Map κ ν

Key κ => Monoid (Map κ ν)

Defined in Core.Data.Structures

Methods

mempty :: Map κ ν

mappend :: Map κ ν -> Map κ ν -> Map κ ν

mconcat :: [Map κ ν] -> Map κ ν

Key κ => Dictionary (Map κ ν)

Defined in Core.Data.Structures

Associated Types

type K (Map κ ν)

type V (Map κ ν)

Methods

fromMap :: Map (K (Map κ ν)) (V (Map κ ν)) -> Map κ ν

intoMap :: Map κ ν -> Map (K (Map κ ν)) (V (Map κ ν))

type Item (Map κ ν)

Defined in Core.Data.Structures

type Item (Map κ ν) = (κ, ν)

type K (Map κ ν)

Defined in Core.Data.Structures

type K (Map κ ν) = κ

type V (Map κ ν)

Defined in Core.Data.Structures

type V (Map κ ν) = ν

emptyMap :: Map κ ν

A dictionary with no key/value mappings.

singletonMap :: Key κ => κ -> ν -> Map κ ν

Construct a dictionary with only a single key/value pair.

insertKeyValue :: Key κ => κ -> ν -> Map κ ν -> Map κ ν

Insert a key/value pair into the dictionary. If the key is already present in the dictionary, the old value will be discarded and replaced with the value supplied here.

containsKey :: Key κ => κ -> Map κ ν -> Bool

Does the dictionary contain the specified key?

lookupKeyValue :: Key κ => κ -> Map κ ν -> Maybe ν

If the dictionary contains the specified key, return the value associated with that key.

Conversions

class Dictionary α where

Types that represent key/value pairs that can be converted to Maps. Haskell's ecosystem has several such. This typeclass provides an adaptor to get between them. It also allows you to serialize out to an association list.

For example, to convert a Map to an "association list" of key/value pairs, use fromMap:

    answers :: Map Rope Int
    answers = singletonMap "Life, The Universe, and Everything" 42

    list :: [(Rope,Int)]
    list = fromMap answers

Instances are provided for containers's Map and unordered-containers's HashMap in addition to the instance for [(κ,ν)] lists shown above.

Associated Types

type K α :: Type

type V α :: Type

Methods

fromMap :: Map (K α) (V α) -> α

intoMap :: α -> Map (K α) (V α)

Instances

Key κ => Dictionary [(κ, ν)]

Defined in Core.Data.Structures

Associated Types

type K [(κ, ν)]

type V [(κ, ν)]

Methods

fromMap :: Map (K [(κ, ν)]) (V [(κ, ν)]) -> [(κ, ν)]

intoMap :: [(κ, ν)] -> Map (K [(κ, ν)]) (V [(κ, ν)])

Key κ => Dictionary (Map κ ν)

from Data.Map.Strict (and .Lazy)

Defined in Core.Data.Structures

Associated Types

type K (Map κ ν)

type V (Map κ ν)

Methods

fromMap :: Map0 (K (Map κ ν)) (V (Map κ ν)) -> Map κ ν

intoMap :: Map κ ν -> Map0 (K (Map κ ν)) (V (Map κ ν))

Key κ => Dictionary (HashMap κ ν)

from Data.HashMap.Strict (and .Lazy)

Defined in Core.Data.Structures

Associated Types

type K (HashMap κ ν)

type V (HashMap κ ν)

Methods

fromMap :: Map (K (HashMap κ ν)) (V (HashMap κ ν)) -> HashMap κ ν

intoMap :: HashMap κ ν -> Map (K (HashMap κ ν)) (V (HashMap κ ν))

Key κ => Dictionary (Map κ ν)

Defined in Core.Data.Structures

Associated Types

type K (Map κ ν)

type V (Map κ ν)

Methods

fromMap :: Map (K (Map κ ν)) (V (Map κ ν)) -> Map κ ν

intoMap :: Map κ ν -> Map (K (Map κ ν)) (V (Map κ ν))

Set type

data Set ε

A set of unique elements.

The element type needs to be an instance of the same Key typeclass that is used for keys in the Map type above. Instances are already provided for many common element types.

Set implements Foldable, Monoid, etc so many common operations such as foldr to walk the elements and reduce them, length to return the size of the collection, null to test whether is empty, and (<>) to take the union of two sets are available.

To convert to other collection types see fromSet below.

(this is a thin wrapper around unordered-containers's HashSet, but if you use the conversion functions to extract a list the list will be ordered according to the elements' Ord instance)

Instances

Foldable Set

Defined in Core.Data.Structures

Methods

fold :: Monoid m => Set m -> m

foldMap :: Monoid m => (a -> m) -> Set a -> m

foldMap' :: Monoid m => (a -> m) -> Set a -> m

foldr :: (a -> b -> b) -> b -> Set a -> b

foldr' :: (a -> b -> b) -> b -> Set a -> b

foldl :: (b -> a -> b) -> b -> Set a -> b

foldl' :: (b -> a -> b) -> b -> Set a -> b

foldr1 :: (a -> a -> a) -> Set a -> a

foldl1 :: (a -> a -> a) -> Set a -> a

toList :: Set a -> [a]

null :: Set a -> Bool

length :: Set a -> Int

elem :: Eq a => a -> Set a -> Bool

maximum :: Ord a => Set a -> a

minimum :: Ord a => Set a -> a

sum :: Num a => Set a -> a

product :: Num a => Set a -> a

Eq ε => Eq (Set ε)

Defined in Core.Data.Structures

Methods

(==) :: Set ε -> Set ε -> Bool

(/=) :: Set ε -> Set ε -> Bool

Show ε => Show (Set ε)

Defined in Core.Data.Structures

Methods

showsPrec :: Int -> Set ε -> ShowS

show :: Set ε -> String

showList :: [Set ε] -> ShowS

Key ε => Semigroup (Set ε)

Defined in Core.Data.Structures

Methods

(<>) :: Set ε -> Set ε -> Set ε

sconcat :: NonEmpty (Set ε) -> Set ε

stimes :: Integral b => b -> Set ε -> Set ε

Key ε => Monoid (Set ε)

Defined in Core.Data.Structures

Methods

mempty :: Set ε

mappend :: Set ε -> Set ε -> Set ε

mconcat :: [Set ε] -> Set ε

Key ε => Collection (Set ε)

Defined in Core.Data.Structures

Associated Types

type E (Set ε)

Methods

fromSet :: Set (E (Set ε)) -> Set ε

intoSet :: Set ε -> Set (E (Set ε))

type E (Set ε)

Defined in Core.Data.Structures

type E (Set ε) = ε

emptySet :: Key ε => Set ε

An empty collection. This is used for example as an inital value when building up a Set using a fold.

singletonSet :: Key ε => ε -> Set ε

Construct a collection comprising only the supplied element.

insertElement :: Key ε => ε -> Set ε -> Set ε

Insert a new element into the collection. Since the Set type does not allow duplicates, inserting an element already in the collection has no effect.

containsElement :: Key ε => ε -> Set ε -> Bool

Does the collection contain the specified element?

Conversions

class Collection α where

Types that represent collections of elements that can be converted to Sets. Haskell's ecosystem has several such. This typeclass provides an adaptor to convert between them.

This typeclass also provides a mechanism to serialize a Set out to a Haskell list. The list will be ordered according to the Ord instance of the element type.

Instances are provided for containers's Set and unordered-containers's HashSet in addition to the instance for [ε] lists described above.

Associated Types

type E α :: Type

Methods

fromSet :: Set (E α) -> α

intoSet :: α -> Set (E α)

Instances

Key ε => Collection [ε]

Defined in Core.Data.Structures

Associated Types

type E [ε]

Methods

fromSet :: Set (E [ε]) -> [ε]

intoSet :: [ε] -> Set (E [ε])

Key ε => Collection (Set ε)

from Data.Set

Defined in Core.Data.Structures

Associated Types

type E (Set ε)

Methods

fromSet :: Set0 (E (Set ε)) -> Set ε

intoSet :: Set ε -> Set0 (E (Set ε))

Key ε => Collection (HashSet ε)

from Data.HashSet

Defined in Core.Data.Structures

Associated Types

type E (HashSet ε)

Methods

fromSet :: Set (E (HashSet ε)) -> HashSet ε

intoSet :: HashSet ε -> Set (E (HashSet ε))

Key ε => Collection (Set ε)

Defined in Core.Data.Structures

Associated Types

type E (Set ε)

Methods

fromSet :: Set (E (Set ε)) -> Set ε

intoSet :: Set ε -> Set (E (Set ε))

Internals

class (Hashable κ, Ord κ) => Key κ

Types that can be used as keys in dictionaries or elements in collections.

To be an instance of Key a type must implement both Hashable and Ord. This requirement means we can subsequently offer easy conversion between different the dictionary and collection types you might encounter when interacting with other libraries.

Instances for this library's Rope and Bytes are provided here, along with many other common types.

Instances

Key Char

Defined in Core.Data.Structures

Key Int

Defined in Core.Data.Structures

Key String

Defined in Core.Data.Structures

Key ByteString

Defined in Core.Data.Structures

Key Text

Defined in Core.Data.Structures

Key Text

Defined in Core.Data.Structures

Key Rope

Defined in Core.Data.Structures

Key Bytes

Defined in Core.Data.Structures

Key JsonKey

Defined in Core.Encoding.Json

unMap :: Map κ ν -> HashMap κ ν

unSet :: Set ε -> HashSet ε