try_for

gistfile1.txt

    /**
     * Executes a function in another task and waits
     * N msecs for it to complete. 
     *
     * # Return Value
     *
     * if the function succeeds, the returned value will
     * be sent back wrapped in result::Ok, otherwise,
     * result::Err will be returned.
     *
     * # Failure
     * Fails if a future_result was already set for this task.
     */                                                                                                                                                                                                                       
    pub fn try_for<T: Send>(&mut self, msecs: u64, f: ~fn() -> T) -> Result<T, ()> {                                                                                                                                                 
        let f = Cell::new(f);

        do self.try {
            let (po, ch) = stream::<T>();

            let f = Cell::new(f.take());

            // Run the function in a separate
            // task. This task will fail if 
            // when its parent ends.
            do spawn { ch.send(f.take()()); }


            let timer = Timer::new();
            // TODO: Handle unwrap error
            let mut t = timer.unwrap();

            // TODO: Fragment waiting time.
            t.sleep(msecs);

            match po.peek() {
                true => po.recv(),
                false => fail!("Timeout")
            }
        }
    }