enums - Rust By Example
Description: A description

# enums

An `enum` is destructured similarly:

    // `allow` required to silence warnings because only
    // one variant is used.
    #[allow(dead_code)]
    enum Color {
        // These 3 are specified solely by their name.
        Red,
        Blue,
        Green,
        // These likewise tie `u32` tuples to different names: color models.
        RGB(u32, u32, u32),
        HSV(u32, u32, u32),
        HSL(u32, u32, u32),
        CMY(u32, u32, u32),
        CMYK(u32, u32, u32, u32),
    }

    fn main() {
        let color = Color::RGB(122, 17, 40);
        // TODO ^ Try different variants for `color`

        println!("What color is it?");
        // An `enum` can be destructured using a `match`.
        match color {
            Color::Red   => println!("The color is Red!"),
            Color::Blue  => println!("The color is Blue!"),
            Color::Green => println!("The color is Green!"),
            Color::RGB(r, g, b) =>
                println!("Red: {}, green: {}, and blue: {}!", r, g, b),
            Color::HSV(h, s, v) =>
                println!("Hue: {}, saturation: {}, value: {}!", h, s, v),
            Color::HSL(h, s, l) =>
                println!("Hue: {}, saturation: {}, lightness: {}!", h, s, l),
            Color::CMY(c, m, y) =>
                println!("Cyan: {}, magenta: {}, yellow: {}!", c, m, y),
            Color::CMYK(c, m, y, k) =>
                println!("Cyan: {}, magenta: {}, yellow: {}, key (black): {}!",
                    c, m, y, k),
            // Don't need another arm because all variants have been examined
        }
    }

### See also:

`#[allow(...)]`, color models and `enum`