Map

2 min read

Import: import system.collections;

Read the usage guide for examples and common tasks. This reference lists the public declarations for this part of the library. See Reading API signatures for parameter and result notation.

Map

A generic open-addressing hash map. Slots are packed {key, value, state} records.

public class Map<K, V>: Collection<KeyValuePair<K, V>>

constructor

Creates an empty map, reserving space based on capacity (8 by default).

public constructor(capacity: int = 8)

reserve

Reserves additional live entries, accounting for load factor and reclaiming tombstones.

public fun reserve(additional: int): Result<Unit, CapacityError>

length

Number of elements currently stored.

public get length(): int

capacity

Number of elements that fit before storage must grow.

public get capacity(): int

this

The first probe hits an empty or matching slot on the usual insert. That case stays in the caller; collisions fall through to the full probe.

public fun this[key: K] = value: V

contains

Returns whether key is present.

public fun contains(borrow key: K): bool

set_all

Inserts corresponding entries from keys and values; the arrays must have equal lengths.

public fun set_all(borrow keys: K[], borrow values: V[]): void

constructor

Creates a map by pairing keys and values up to the shorter array length; later duplicate keys replace earlier values.

public constructor(borrow keys: K[], borrow values: V[])

get

Value for key, or None when absent.

public fun get(borrow key: K): Option<V>

get

Value for the string key equal to key, without building a string.

public fun get(borrow key: ReadOnlySpan<char>): Option<V> where K: StringKey

contains

Returns whether key is present.

public fun contains(borrow key: ReadOnlySpan<char>): bool where K: StringKey

this

Value for key. Panics when the key is absent — this is what m[k] compiles to; use get(k) for absence-tolerant reads.

public fun this[borrow key: K]: V

get_or_insert

Returns the existing value, or inserts and returns the result of factory when absent. The key is borrowed for the lookup and copied only on a miss.

public fun get_or_insert(borrow key: K, borrow factory: fun(): V): V

merge

Copies entries from other, replacing values with matching keys.

public fun merge(borrow other: Map<K, V>): void

entries

Returns a new list of key/value pairs.

public fun entries(): List<KeyValuePair<K, V>>

remove

Removes key and its value; returns whether the key was present.

public fun remove(borrow key: K): bool

is_empty

Returns whether there are no elements.

public fun is_empty(): bool

clear

Removes all entries while keeping storage for reuse.

public fun clear(): void

clear

Removes all entries while keeping storage for reuse.

public fun clear(): void where K: unmanaged, V: unmanaged

keys

Returns a new list of the keys, in the map's iteration order.

public fun keys(): List<K>

values

Returns a new list of the values, in the map's iteration order.

public fun values(): List<V>

iterator

Creates a cursor over the sequence. Close it when iteration ends early.

public fun iterator(): MapIterator<K, V>

to_string

Returns a text representation of this value.

public override fun to_string(): string