Listening for Events

Intro

Tourmaline provides event listeners which are fired every time one of several UpdateAction's is fired.

Event Listener Annotation

Like commands, it's possible to annotate a method with an On annotation to designate that method as an event listener.On accepts any of the UpdateAction's as an argument (although you can use symbols as well) and passes in an EventContext every time that update is seen.

As an example, let's listen for text messages and print them to the console:

@[On(:text)]
def text_listener(ctx : EventHandler)
  if message = ctx.message
    logger.debug("Text: #{message.text}")
  end
end

As with the Command annotation, the On annotation also has a handler counterpart in the EventHandler, which works in much the same way.