I want to have an enum where each value in the enum stores a constant array of bytes that represent the RGBA values for a color. In Java I would do this:
public enum Color {
BLACK([0x0C, 0x00, 0x05, 0xFF]),
BLUE([0x00, 0x2D, 0xFF, 0xFF]),
RED([0xFF, 0x3E, 0x00, 0xFF]);
private final byte[] rgba;
Color(byte[] rgba) {
this.rgba = rgba;
}
public int[] value() {
return rgba;
}
}
Then I could pass around Color types and just use color.value() to get the bytes out. This is what I have in Rust:
struct Color;
impl Color {
pub const BLACK: [u8; 4] = [0x0C, 0x00, 0x05, 0xFF];
pub const BLUE: [u8; 4] = [0x00, 0x2D, 0xFF, 0xFF];
pub const RED: [u8; 4] = [0xFF, 0x3E, 0x00, 0xFF];
}
But this means that anywhere I want to pass a Color the type is [u8; 4]. I could call the struct Colors and then do pub type Color = [u8; 4]. Then you could have the type as Color but then it would be Colors::BLACK which seems weird.
If you want to have a strong type for the byte array in the Color struct, you can use the following notation, called a tuple struct:
struct Color([u8; 4]);
impl Color {
pub const BLACK: Color = Color([0x0C, 0x00, 0x05, 0xFF]);
pub const BLUE: Color = Color([0x00, 0x2D, 0xFF, 0xFF]);
pub const RED: Color = Color([0xFF, 0x3E, 0x00, 0xFF]);
}
fn main() {
// classic way of accessing data
println!("{:?}", Color::BLACK.0);
// using destructuring
let Color(bytes) = Color::BLUE;
println!("{:?}", bytes);
}
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