How would I implement an event registry?

[J-Cake]

Hi, I'm using rlua for a plugin system where I need to expose event handler functions. I wish to achieve this by capturing a set of predefined globals. If they're functions, call them when ever the corresponding event occurs. Take the following lua code:

function on_event_1(event)
  print("Event 1")
end

function not_an_event_handler()
  print("Not an event handler")
end

I'd capture the handlers like so:

lua.context(|ctx| {
  // ...
  ctx.load(/*code*/).exec();

  if let Ok(handler) = ctx.globals().get::<_, rlua::Function>("on_event_1") { 
    self.on_event_1 = handler;
  }

});

But I get issues because the ctx object is leaked from the closure. Makes sense, the plugin outlives the context.

My question would be about what the best way to achieve this would be?

[jugglerchris]

Hi,
I think what you want is probably Context::create_registry_value to create a reference you can store outside of the context, along with Context::registry_value to retrieve it when needed.

Chris

[J-Cake]

Hi Chris,

Thanks for your quick reply. I ended up using your suggestion and it's working well. (my project isn't huge yet so it was an easy implementation)

Thanks
Jake

[jugglerchris]

Great, glad to hear it!