Attribute Macro observer

#[observer]

Registers an observer function to a #[butler_plugin]-annotated Plugin.

Usage

On a free-standing function

#[observer(plugin = MyPlugin)]
fn receive_message(message: Trigger<Message>) {
    info!("Message received: {}", message.content);
}

On an imported function

#[observer(plugin = MyPlugin)]
use my_mod::receive_message;

For more information about Observers, see the Bevy example.

Arguments

plugin (Required)

A Plugin annotated with #[butler_plugin] to register this observer to.

generics

A list of generic arguments to register the observer with. Used to register a generic observer for multiple different types.