Different Event Paradigms

[dubrowgn]

I've been playing around with BMS for a couple of weeks. It pretty impressive!

As far as I can tell, the only way to handle events is via ScriptCallbackEvent + event_handler::<OnEvent, LuaScriptingPlugin>. This works, but is fairly boilerplate heavy on the rust side, needing two sets of event registration types/code, and relatively opinionated since event_handler handles the dispatch in a specific way. Are there plans to make event handling more inline with bevy in the future? Specifically:

1. EventReader<E> / EventWriter<E>

Being able to use EventReader and EventWriter natively from script systems via system_builder. A cache/performance friendly way to handle lots of the same kind of event. Theoretically, no BMS specific registrations or boilerplate needed.

2. Trigger<E>

Being able to use Trigger<E> natively from script systems via system_builder. Theoretically, no BMS specific registrations or boilerplate needed.

3. One-off ScriptCallbackEvent-like dispatch

An easy way to manually dispatch a script event handler. Basically what event_handler already does, just for a single event. Maybe this can even be abstracted to easily dispatch any script function by name, where event handling is just one use case.

Note: I'm using the pre-v0.17 bevy event/trigger terms.