Arrays, Slices and Ranges

Arrays

Fixed-size collection, size known at compile time. Elements access with a[i], indexing starts at 0.
Syntax:

[1, 2, 3, 4]
[0; 1024]

The array type is [N]T ([0; 1024] is [1024]i32).

If elements are not Copy, the array is move-only.

Example:

let numbers = [10, 20, 30];

numbers[0] = 99;

@println("{} {}", numbers[0], numbers[2]);

Out of bounds access panics in Debug, in Release it is UB.

Slices

A slice is a view into array data with a pointer and a length. It does not copy data, writes through the slice change the original array.
Syntax:

numbers[1..4]
numbers[..]
numbers[..3]
numbers[2..]
numbers[1..=3]

The slice type is []T. Slices have .len and .ptr fields. A slice is always Copy, it is just a view.

Example:

let numbers = [1, 2, 3, 4, 5];
let slice = numbers[1..4];

slice[0] = 99;

@println("{} {}", slice.len, slice[0]);

Out of bounds access panics in Debug, in Release it is UB.

Ranges

A range is a core type with optional bounds, used for slicing and iteration.
Syntax:

lo..hi
lo..=hi
lo..
..hi
..=hi
..

Ranges can be assigned to a variable:

let range: Range = 1..4;

Example:

let range = 0..3;

for (i : range) {
  @println("{}", i);
}

Many Pointers

C-like pointer with unknown length, elements access with ptr[i].
Can be made from array:

let numbers = [1, 2, 3];
let ptr: [*]i32 = numbers;

Example:

let numbers = [104, 101, 108];
let ptr: [*]i32 = numbers;

ptr[1] = 121;

@println("{} {}", ptr[0], ptr[1]);