Module events 

Different types of events.

Events should be used to coordinate between spawned tasks so that they can run in an event-driven manner and yield until there is something ready to process.

Basic events are created to be triggered once using notify() method. Any number of other tasks can be waiting for the event to be triggered. The listen() method is used to wait for the event to be triggered.

The engine provides a small set of event types that cover the common coordination patterns used by components and models:

• Once: fires exactly once and wakes every listener with a fixed result value. This is useful for completion, timeout, and one-off handshakes.
• Repeated: can fire many times and wakes listeners waiting for the next generation. This is useful for state changes, monitor updates, and reusable notifications.
• AnyOf: combines several events and wakes when the first one fires, returning that event’s result. This is useful for races such as response-or-timeout waits.
• AllOf: combines several events and wakes once they have all fired. This is useful for joining setup, drain, or completion conditions.

Example:

An event being created to co-ordinate between two tasks.

fn spawn_listen<T>(engine: &mut Engine, event: Once<T>)
where
    T: Copy + 'static,
{
    engine.spawn(async move {
        event.listen().await;
        println!("After event");
        Ok(())
    });
}

fn spawn_notify<T>(engine: &mut Engine, event: Once<T>)
where
    T: Copy + 'static,
{
    let clock = engine.default_clock();
    engine.spawn(async move {
        clock.wait_ticks(10).await;
        println!("Trigger event");
        event.notify()?;
        Ok(())
    });
}

fn main() {
    let mut engine = Engine::default();
    let event = Once::default();
    spawn_listen(&mut engine, event.clone());
    spawn_notify(&mut engine, event);
    run_simulation!(engine);
}

Modules

all_of

An event that is triggered when all events in the provided set are triggered.

any_of

An event that is triggered when one event in the provided set is triggered.

once

An event that can only be triggered once

repeated

An event that can be triggered multiple times. The event allows the notifier to pass a custom result to its listeners on each notification, using the notify_result() method. Alternatively, the last set result will be provided to the listeners. If no result has been set, the default value for the result type will be used.