traits thing

gistfile1.txt

#[warn(no_vecs_not_implicitly_copyable)];

iface to_str {
    fn to_str() -> str;
}

impl of to_str for int {
    fn to_str() -> str { int::to_str(self, 10u) }
}
impl of to_str for str {
    fn to_str() -> str { self }
}

impl extensions<A: to_str> for A {
    fn exclaim() -> str { self.to_str() + "!" }
}

fn exclaim<T: to_str>(x: T) {
    io::println(x.exclaim());
}

fn main() {
    exclaim(5);
    exclaim("hello, world");
}