Array

Arrays are Ard’s fixed-length ordered collections. An array type is written [T; N], where T is the element type and N is the length.

let rgb: [Byte; 3] = [255, 128, 0]
let empty: [Int; 0] = []

The length is part of the type, so [Byte; 3] and [Byte; 4] are different types.

Methods

fn size() Int

Return the array length.

let rgb: [Byte; 3] = [255, 128, 0]
let count = rgb.size() // 3

fn at(index: Int) T?

Return the element at index, or Maybe::new<T>() if the index is out of bounds.

let rgb: [Byte; 3] = [255, 128, 0]
let zero: Byte = 0
let red = rgb.at(0).or(zero)
let missing = rgb.at(9) // Byte?

Construction

Arrays use normal list literal syntax with an expected array type. The literal length must match exactly.

let point: [Int; 2] = [10, 20]

This is an error because the length does not match:

let point: [Int; 2] = [10, 20, 30]

Lists vs arrays

Use [T] for growable lists and [T; N] for fixed-size arrays. There is no implicit list-to-array or array-to-list conversion.