rust/src/test/run-pass/anon-obj-cats.rs

fn main() {

    // The Internet made me do it.

    obj cat() {
        fn ack() -> str { ret "ack"; }
        fn meow() -> str { ret "meow"; }
        fn zzz() -> str { ret self.meow(); }
    }

    let shortcat = cat();

    let longcat =
        obj () {
            fn lol() -> str { ret "lol"; }
            fn nyan() -> str { ret "nyan"; }
            with
            shortcat
        };

    let longercat =
        obj () {
            fn meow() -> str { ret "zzz"; }
            with
            shortcat
        };

    let evenlongercat =
        obj () {
            fn meow() -> str { ret "zzzzzz"; }
            with
            longercat
        };

    // Tests self-call.
    assert (shortcat.zzz() == "meow");

    // Tests forwarding/backwarding + self-call.
    assert (longcat.zzz() == "meow");

    // Tests forwarding/backwarding + self-call + override.
    assert (longercat.zzz() == "zzz");

    // Tests two-level forwarding/backwarding + self-call + override.
    assert (evenlongercat.zzz() == "zzzzzz");
}