const_array_map

A no_std-compatible, const-capable Map type backed by an array.

This crate defines a new map type, ConstArrayMap, similar to other data structures but implemented using a single array with zero-cost conversion between keys and array indices.

Currently, keys are limited to enums with a primitive representation. In the future, it might also be possible to support arbitrary types with a relatively small number of distinct valid values, possibly at the expense of not exposing const-qualified methods for these key types.

Example

use const_array_map::{const_array_map, PrimitiveEnum};

#[repr(u8)]
#[derive(Copy, Clone, PrimitiveEnum)]
enum Letter {
    A,
    B,
    C,
}

fn main() {
    let letters = const_array_map! {
        Letter::A => 'a',
        Letter::B => 'b',
        Letter::C => 'c',
    };

    assert_eq!(letters[Letter::A], 'a');
    assert_eq!(letters[Letter::C], 'c');
}