extern crate sync;
use sync::mutex::{Mutex,Guard};
use std::task;

fn lock<'a>(l0 : &'a Mutex, l1 : &'a Mutex) -> (Guard<'a>, Guard<'a>) {
    loop {
        't0: for _ in range(0u, 1u) {
            let u0 = l0.lock();
            let u1 = match l1.try_lock() {
                None => {
                    drop(u0);
                    break 't0;
                }
                Some(g) => g
            };
            return (u0, u1);
        }
        task::deschedule();
        't1: for _ in range(0u, 1u) {
            let u1 = l1.lock();
            let u0 = match l1.try_lock() {
                None => {
                    drop(u1);
                    break 't1;
                }
                Some(g) => g
            };
            return (u0, u1);
        }
        task::deschedule();
    }
}

fn main() {
    let a = Mutex::new();
    let b = Mutex::new();
    let (g0, g1) = lock(&a, &b);
}