Prototype relm API usage

example.rs

#[test]
fn simple_test() {
    // A Mailbox consists of an Address and a Signal.
    // Values sent into the Address show up as events on the Signal.
    let input1 = Mailbox::new(0); // The default value of this input is 0.
    let input2 = Mailbox::new(0);
    let input3 = Mailbox::new(0);
    // This test demonstrates updates propagating from a lift2's inputs updating all at once and one at a time.
    let mapped = lift2(
        lift2(input1.signal, input3.signal.clone(), |x, y| x + y), // Both this signal
        lift2(input2.signal, input3.signal, |x, y| x + y), // and this one are triggered by updates to input3
        |x, y| x + y); // This signal is triggered by all the inputs
    let runtime = Runtime::new(mapped, 4); // 4 is the number of worker threads to use
    // Inputs go in:
    input1.address.send(1);
    input2.address.send(2);
    input3.address.send(1); // input3 update causes all lift2 nodes to recompute
    // and results come out (default value first):
    assert_eq!(runtime.next_blocking(), 0); // (0 + 0) + (0 + 0) 
    assert_eq!(runtime.next_blocking(), 1); // (1 + 0) + (0 + 0)
    assert_eq!(runtime.next_blocking(), 3); // (1 + 0) + (2 + 0)
    assert_eq!(runtime.next_blocking(), 5); // (1 + 1) + (2 + 1)
}