Std.Dict - Saga

Immutable key-value dictionaries backed by Erlang maps.

Functions

fun new : Unit -> Dict k v

Creates an empty dictionary.

fun from_list : (pairs: List (k, v)) -> Dict k v where {k: Eq}

Creates a dictionary from a list of key-value pairs.

fun get : (key: k) -> (dict: Dict k v) -> Maybe v where {k: Eq}

Returns the value for a key, or Nothing if not present.

fun put : (key: k) -> (value: v) -> (dict: Dict k v) -> Dict k v where {k: Eq}

Inserts or replaces a key-value pair.

fun remove : (key: k) -> (dict: Dict k v) -> Dict k v where {k: Eq}

Removes a key from the dictionary. Returns the dict unchanged if key is not present.

fun member : (key: k) -> (dict: Dict k v) -> Bool where {k: Eq}

Returns True if the key is present in the dictionary.

fun size : (dict: Dict k v) -> Int

Returns the number of entries in the dictionary.

fun is_empty : Dict k v -> Bool

Returns True if the dictionary has no entries.

fun keys : (dict: Dict k v) -> List k

Returns all keys as a list.

fun values : (dict: Dict k v) -> List v

Returns all values as a list.

fun to_list : (dict: Dict k v) -> List (k, v)

Converts the dictionary to a list of key-value pairs.

fun map : (f: v -> v2) -> (dict: Dict k v) -> Dict k v2

Applies a function to every value, returning a new dictionary.

fun filter : (pred: k -> v -> Bool) -> (dict: Dict k v) -> Dict k v

Returns a dictionary containing only entries where the predicate returns True.

fun fold : (f: a -> k -> v -> a) -> (init: a) -> (dict: Dict k v) -> a

Folds over all entries, left to right.

fun merge : (base: Dict k v) -> (overrides: Dict k v) -> Dict k v where {k: Eq}

Merges two dictionaries. Values from the overrides dict win on key conflicts.

fun update : (key: k) -> (f: v -> v) -> (dict: Dict k v) -> Dict k v where {k: Eq}

Updates the value at a key by applying a function. No-op if key is not present.