Rust解構枚舉
枚舉同樣也可以解構:
// Must derive `Debug` so `println!` can be used. // `allow` required to silence warnings because only // one variant is used. #[allow(dead_code)] #[derive(Debug)] 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 } }