Silex application concept which uses the PHP $GLOBALS array as the service container.

GlobalsApplication.php

<?php

use Silex\Application;

class GlobalsApplication extends Application
{
    public function __construct(array $values = array())
    {
        // Set up the Silex services.
        parent::__construct($values);

        // Set aside Silex services and substitute a reference to the PHP globals array.
        $values = $this->values;
        $this->values = &$GLOBALS + $values;
    }

    /**
     * {@inheritdoc}
     */
    public function keys()
    {
        // This helps prevent recursion errors.
        return array_diff(parent::keys(), ['GLOBALS', 'app']);
    }
}