Playing with Rust

union.rs

#![feature(struct_variant)]

extern crate debug;

enum Direction {
    Up, Down, Left, Right
}

/*
use std::fmt;
impl Direction {
    fn string(&self) -> &str {
        match *self {
            Up => "Up",
            Down => "Down",
            Left => "Left",
            Right => "Right"
        }
    }
}
impl std::fmt::Show for Direction {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{}", self.string())
    }
}
*/

struct Point {
    x: f64, y: f64
}

enum Shape {
    Circle { center: Point, radius: f64 },
    Arrow { center: Point, direction: Direction },
    Trapezoid
}

fn write_shape(s: Shape) {
    match s {
        Circle { center, radius } => println!(
                                        "Circle x={}, y={}, r={}",
                                        center.x,
                                        center.y,
                                        radius
                                        ),
        Arrow { center, direction } => println!(
                                        "Arrow x={}, y={}, d={:?}",
                                        center.x,
                                        center.y,
                                        direction
                                        ),
        _ => println!("Unknown shape")

    }
}

fn main() {
    write_shape(Circle { center: Point{ x: 1.0, y: 1.0 }, radius: 1.0 });
    write_shape(Arrow { center: Point{ x: 0.5, y: 0.5 }, direction: Up });
    write_shape(Trapezoid);
}