3 #![allow(non_camel_case_types)]
4 #![allow(non_snake_case)]
6 #![feature(box_syntax)]
8 // Example from lkuper's intern talk, August 2012 -- now with static
10 use Color::{cyan, magenta, yellow, black};
11 use ColorTree::{leaf, branch};
14 fn isEq(a: &Self, b: &Self) -> bool;
17 #[derive(Clone, Copy)]
18 enum Color { cyan, magenta, yellow, black }
20 impl Equal for Color {
21 fn isEq(a: &Color, b: &Color) -> bool {
23 (cyan, cyan) => { true }
24 (magenta, magenta) => { true }
25 (yellow, yellow) => { true }
26 (black, black) => { true }
35 branch(Box<ColorTree>, Box<ColorTree>)
38 impl Equal for ColorTree {
39 fn isEq(a: &ColorTree, b: &ColorTree) -> bool {
41 (&leaf(ref x), &leaf(ref y)) => {
42 Equal::isEq(&(*x).clone(), &(*y).clone())
44 (&branch(ref l1, ref r1), &branch(ref l2, ref r2)) => {
45 Equal::isEq(&(**l1).clone(), &(**l2).clone()) &&
46 Equal::isEq(&(**r1).clone(), &(**r2).clone())
54 assert!(Equal::isEq(&cyan, &cyan));
55 assert!(Equal::isEq(&magenta, &magenta));
56 assert!(!Equal::isEq(&cyan, &yellow));
57 assert!(!Equal::isEq(&magenta, &cyan));
59 assert!(Equal::isEq(&leaf(cyan), &leaf(cyan)));
60 assert!(!Equal::isEq(&leaf(cyan), &leaf(yellow)));
62 assert!(Equal::isEq(&branch(box leaf(magenta), box leaf(cyan)),
63 &branch(box leaf(magenta), box leaf(cyan))));
65 assert!(!Equal::isEq(&branch(box leaf(magenta), box leaf(cyan)),
66 &branch(box leaf(magenta), box leaf(magenta))));
68 println!("Assertions all succeeded!");