Observable.php

<?php

trait Observable
{
    protected $subscribers = [];

    public function on($name, $fn)
    {
        if (empty($this->subscribers[$name])) {
            $this->subscribers[$name] = [];
        }

        $this->subscribers[$name][] = $fn;

        return $this;
    }

    public function off($name, $fn)
    {
        unset($this->subscribers[$name][array_search($fn, $this->subscribers[$name])]);

        return $this;
    }

    public function fire($name, ...$params)
    {
        $subscribers = array_filter($this->subscribers, function($eventName) use ($name) {
            return fnmatch($eventName, $name);
        }, ARRAY_FILTER_USE_KEY);
        
        foreach ($subscribers as $eventName => $fns) {
            foreach ($fns as $fn) {
                $fn(...$params);
            }
        }
    }
}

class Mediator
{
    use Observable;
}

$p = function() { echo 'a'; };

$m = new Mediator;
$m->on('*.finish', $p);
$m->fire('uber.finish');