rustlings/exercises/enums/enums3.rs

// enums3.rs
// Address all the TODOs to make the tests pass!

enum Message {
    // TODO: implement the message variant types based on their usage below
    // // solution0
    // ChangeColor((u8, u8, u8)),
    // Echo(String),
    // Move(Point),
    // Quit,
    // solution1
    ChangeColor { color: (u8, u8, u8) },
    Echo { s: String },
    Move { p: Point },
    Quit,
}

struct Point {
    x: u8,
    y: u8,
}

struct State {
    color: (u8, u8, u8),
    position: Point,
    quit: bool,
}

impl State {
    fn change_color(&mut self, color: (u8, u8, u8)) {
        self.color = color;
    }

    fn quit(&mut self) {
        self.quit = true;
    }

    fn echo(&self, s: String) {
        println!("{}", s);
    }

    fn move_position(&mut self, p: Point) {
        self.position = p;
    }

    fn process(&mut self, message: Message) {
        // TODO: create a match expression to process the different message variants
        match message {
            // // solution0
            // Message::ChangeColor((r, g, b)) => self.change_color((r, g, b)),
            // Message::Echo(s) => self.echo(s),
            // Message::Move(p) => self.move_position(p),
            // Message::Quit => self.quit(),
            // solution1
            Message::ChangeColor { color } => self.change_color(color),
            Message::Echo { s } => self.echo(s),
            Message::Move { p } => self.move_position(p),
            Message::Quit => self.quit(),
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_match_message_call() {
        let mut state = State {
            quit: false,
            position: Point { x: 0, y: 0 },
            color: (0, 0, 0),
        };
        // // solution0
        // state.process(Message::ChangeColor((255, 0, 255)));
        // state.process(Message::Echo(String::from("hello world")));
        // state.process(Message::Move(Point { x: 10, y: 15 }));
        // state.process(Message::Quit);
        // solution1
        state.process(Message::ChangeColor {
            color: (255, 0, 255),
        });
        state.process(Message::Echo {
            s: String::from("hello world"),
        });
        state.process(Message::Move {
            p: Point { x: 10, y: 15 },
        });
        state.process(Message::Quit);

        assert_eq!(state.color, (255, 0, 255));
        assert_eq!(state.position.x, 10);
        assert_eq!(state.position.y, 15);
        assert_eq!(state.quit, true);
    }
}