gecko-dev/third_party/rust/generic-array/README.md

generic-array

This crate implements generic array types for Rust.

Documentation

Usage

The Rust arrays [T; N] are problematic in that they can't be used generically with respect to N, so for example this won't work:

struct Foo<N> {
	data: [i32; N]
}

generic-array defines a new trait ArrayLength<T> and a struct GenericArray<T, N: ArrayLength<T>>, which let the above be implemented as:

struct Foo<N: ArrayLength<i32>> {
	data: GenericArray<i32, N>
}

To actually define a type implementing ArrayLength, you can use unsigned integer types defined in typenum crate - for example, GenericArray<T, U5> would work almost like [T; 5] :)

In version 0.1.1 an arr! macro was introduced, allowing for creation of arrays as shown below:

let array = arr![u32; 1, 2, 3];
assert_eq!(array[2], 3);