Macro macro_bits::incomplete_const_array

macro_rules! incomplete_const_array {
    (
        #[filler($filler:expr)]
        $(#[$const_attr:meta])*
        $const_vis:vis const $const_name:ident: [$array_type:ty; $array_length:expr] = [
            $(
                $idx:expr => $value:expr
            ),*
        ];
    ) => { ... };
}

Allows the creation of a const array without specifying all elements.

use macro_bits::incomplete_const_array;
 
incomplete_const_array! {
    #[filler(0)] // Has to be first.
    /// Just some array.
    pub const ARRAY: [usize; 4] = [
        1 => 1337,
        3 => 42
    ];
}
assert_eq!(ARRAY, [0, 1337, 0, 42]);