aivi.core.dict

aivi.core.dict provides an immutable association map for keys with an Eq instance. A Dict K V stores entries in a list, so lookup, insertion, and removal take linear time. Building a dictionary with repeated insertion can take quadratic time. Use it for small maps in the MVP.

The empty dictionary is { entries: [] }. insert places a new or replaced key first. fromList processes pairs from left to right, so the final occurrence of a duplicate key wins and appears first.

Type class operations

Dict K implements Functor, Foldable, Traversable, and Filterable. Ambient map transforms values, reduce folds them in entry order, and filterMap removes entries whose transformed value is None. Keys and the relative order of retained entries are preserved. Default (Dict K V) creates an empty dictionary. These operations do not require Eq K because they never compare or insert keys.

traverse transform dictionary sequences values through any Applicative G, producing G (Dict K B). Every resulting dictionary keeps the original keys and entry order. An empty dictionary is lifted with pure. Task effects run in entry order when the plan is executed.

mapValues remains the explicitly named equivalent of map. There is no implicit class-level merge policy for dictionaries.

API

Export	Type	Behavior
Dict	Dict K V	Association-map record type
singleton	K -> V -> Dict K V	Create one entry
insert	Eq K => K -> V -> Dict K V -> Dict K V	Insert or replace a value
insertWith	Eq K => (V -> V -> V) -> K -> V -> Dict K V -> Dict K V	Combine an existing value with a new value
get	Eq K => K -> Dict K V -> Option V	Look up a key
getWithDefault	Eq K => V -> K -> Dict K V -> V	Look up a key with a fallback
member	Eq K => K -> Dict K V -> Bool	Test whether a key exists
remove	Eq K => K -> Dict K V -> Dict K V	Remove a key
size	Dict K V -> Int	Count entries
keys	Dict K V -> List K	Return keys in entry order
values	Dict K V -> List V	Return values in entry order
toList	Dict K V -> List (K, V)	Return key/value pairs in entry order
fromList	Eq K => List (K, V) -> Dict K V	Build a dictionary from pairs
mapValues	(V1 -> V2) -> Dict K V1 -> Dict K V2	Transform every value
filterValues	(V -> Bool) -> Dict K V -> Dict K V	Keep entries whose values pass a predicate

use aivi.core.dict (
    Dict
    get
    insert
)

value scores : Dict Text Int =
    insert "Ada" 10 {
        entries: []
    }

value adaScore : Option Int = get "Ada" scores