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//@ run-pass
#![allow(non_camel_case_types)]
#![allow(non_snake_case)]
#![allow(dead_code)]
// Example from lkuper's intern talk, August 2012 -- now with static
// methods!
use Color::{cyan, magenta, yellow, black};
use ColorTree::{leaf, branch};
trait Equal {
fn isEq(a: &Self, b: &Self) -> bool;
}
#[derive(Clone, Copy)]
enum Color { cyan, magenta, yellow, black }
impl Equal for Color {
fn isEq(a: &Color, b: &Color) -> bool {
match (*a, *b) {
(cyan, cyan) => { true }
(magenta, magenta) => { true }
(yellow, yellow) => { true }
(black, black) => { true }
_ => { false }
}
}
}
#[derive(Clone)]
enum ColorTree {
leaf(Color),
branch(Box<ColorTree>, Box<ColorTree>)
}
impl Equal for ColorTree {
fn isEq(a: &ColorTree, b: &ColorTree) -> bool {
match (a, b) {
(&leaf(ref x), &leaf(ref y)) => {
Equal::isEq(&(*x).clone(), &(*y).clone())
}
(&branch(ref l1, ref r1), &branch(ref l2, ref r2)) => {
Equal::isEq(&(**l1).clone(), &(**l2).clone()) &&
Equal::isEq(&(**r1).clone(), &(**r2).clone())
}
_ => { false }
}
}
}
pub fn main() {
assert!(Equal::isEq(&cyan, &cyan));
assert!(Equal::isEq(&magenta, &magenta));
assert!(!Equal::isEq(&cyan, &yellow));
assert!(!Equal::isEq(&magenta, &cyan));
assert!(Equal::isEq(&leaf(cyan), &leaf(cyan)));
assert!(!Equal::isEq(&leaf(cyan), &leaf(yellow)));
assert!(Equal::isEq(&branch(Box::new(leaf(magenta)), Box::new(leaf(cyan))),
&branch(Box::new(leaf(magenta)), Box::new(leaf(cyan)))));
assert!(!Equal::isEq(&branch(Box::new(leaf(magenta)), Box::new(leaf(cyan))),
&branch(Box::new(leaf(magenta)), Box::new(leaf(magenta)))));
println!("Assertions all succeeded!");
}
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