events

Use events to decouple code with named in-process events. Listeners run synchronously on the thread that emits, and registration and emission are safe from any thread.

import "std:events"

def onScore(int points) (
  log "scored " ++ points
)

events.on("score", onScore)
events.emit("score", 10)
events.off("score", onScore)

API reference

Method	Returns	Notes
events.on(name: string, callback: function)	void	Adds a listener. The same function may be added more than once.
events.off(name: string, callback: function)	boolean	Removes the first matching listener and reports whether one was removed.
events.emit(name: string, ...args)	void	Calls every listener registered for name with args, in registration order.

emit calls the listeners registered when it starts, so a listener can add or remove listeners without affecting the current emission. Listeners may emit events recursively. A panic in a listener propagates to the caller of emit.