Lime\App::on PHP Method

    public function on($event, $callback, $priority = 0)
    {
        if (!isset($this->events[$event])) {
            $this->events[$event] = [];
        }
        // make $this available in closures
        if (is_object($callback) && $callback instanceof \Closure) {
            $callback = $callback->bindTo($this, $this);
        }
        $this->events[$event][] = ["fn" => $callback, "prio" => $priority];
        return $this;
    }