array

build

fn(initial_state: 'a, step_fn: fn ('a) -> ('a, 'b, Bool) / 't109) -> (Array<'b>, 'a) / 't109

Builds an array by repeatedly calling step_fn(state) -> (new_state, value, done). Always produces at least 1 element. Returns (array, final_state).

concat

fn(left: Array<'t>, right: Array<'t>) -> Array<'t>

Concatenates two arrays, returning a new array that contains the items in left followed by the items in right.

filter

fn(arr: Array<'t>, predicate: fn ('t) -> Bool / 't708) -> Array<'t> / { 't708, 't708, 't708, ..'t708 }

Returns a new array containing only items for which predicate returns true. If all items pass, returns the original array (preserving referential equality).

filter_map

fn(array: Array<'a>, f: fn ('a) -> Option<'b> / 't781) -> Array<'b> / { 't781, 't781, 't781, ..'t781 }

Returns a new array containing only the elements for which f returns Some, unwrapping the values. Elements for which f returns None are skipped.

first

fn(array: Array<'t>) -> Option<'t>

Returns the first item in the array, or None if it is empty.

fold_right

fn(array: Array<'a>, init: 'b, reducer: fn ('b, 'a) -> 'b / 't627) -> 'b / { 't627, ..'t628 }

get

fn(array: Array<'t>, index: Int) -> Option<'t>

Returns the item at the given index, or None if the index is out of bounds.

import core/option { Some, None }
let a = [1, 2, 3];
test.assert_eq(array.get(a, 1), Some(2));
test.assert_eq(array.get(a, 5), None);

head

fn(array: Array<'t>) -> Array<'t>

Returns a new array containing all but the last item in this array.

insert

fn(array: Array<'t>, index: Int, item: 't) -> Array<'t>

Returns a new array with the item inserted at the given index, shifting subsequent elements to the right.

last

fn(array: Array<'t>) -> Option<'t>

Returns the last item in the array, or None if it is empty.

length

fn(array: Array<'t>) -> Int

Returns the length of the array.

map

fn(array: Array<'a>, map_fn: fn ('a) -> 'b / 't644) -> Array<'b> / 't644

map_with_accumulator

fn(array: Array<'a>, acc: 'acc, f: fn ('acc, 'a) -> ('acc, 'b) / 't203) -> (Array<'b>, 'acc) / 't203

Maps over an array while threading an accumulator through each step. f(acc, item) -> (new_acc, mapped_item). Returns (mapped_array, final_acc).

new

∀ 't . fn () -> Array<'t>

Creates a new empty array.

new_from

fn(length: Int, offset: Int, map_fn: fn (Int) -> 't / 't360) -> Array<'t> / 't360

Creates a new array of length length, filling each index n with the result of mapFn(n).

pop

fn(array: Array<'t>) -> (Array<'t>, Option<'t>)

Removes the list item from an array, returning a new array and the removed item.

push

fn(array: Array<'t>, item: 't) -> Array<'t>

Returns a new array with the item appended to the end, without modifying the original array.

reduce

fn(array: Array<'a>, start: 'b, reducer: fn ('b, 'a) -> 'b / 't604) -> 'b / { 't604, ..'t605 }

remove

fn(array: Array<'t>, index: Int) -> (Array<'t>, Option<'t>)

Returns a new array with the item at the given index removed, without modifying the original array, and the value that was previously at that index.

remove_at

fn(arr: Array<'t>, index: Int) -> Array<'t>

Returns a new array with the item at the given index removed. Does not return the removed value. No bounds checking.

set

fn(array: Array<'t>, index: Int, value: 't) -> Array<'t>

Returns a new array, updating the item at the given index to the new value.

If the index is outside the bounds of the array, the original array is returned.

singleton

fn(item: 't) -> Array<'t>

Creates a new array containing a single item.

slice

fn(array: Array<'t>, start: Int, end: Int) -> Array<'t>

Returns a new array containing elements from index start (inclusive) to index end (exclusive). Returns the original array if bounds are invalid.

tail

fn(array: Array<'t>) -> Array<'t>

Returns a new array containing all but the first item in this array.

unchecked_get

fn(array: Array<'t>, index: Int) -> 't

Returns the item at the given index without bounds checking.

unchecked_pop

fn(array: Array<'t>) -> (Array<'t>, 't)

Removes the list item from an array, returning a new array and the removed item, without bounds checking.

unchecked_set