square.rs

fn square(merge_chan: Sender<PipelineMsg>) -> Sender<PipelineMsg> {
    let (chan, port) = channel();
    let _ = thread::Builder::new().spawn(move || {
        // Iteration will stop,
        // once the sender returned by "square" is dropped.
        for msg in port {
            let num = match msg {
                PipelineMsg::Generated(num) => num,
                _ => panic!("unexpected message receiving at square stage"),
            };
            // Sending squared numbers on to the "merge" stage...
            let _ = merge_chan.send(PipelineMsg::Squared(num * num));
        }
    });
    // Sharing our sender with the world...
    chan
}