Oppa js style (silex-based skeleton without unintended global variables

app.php

<?php
return call_user_func(function() {
    $app = new \Silex\Application();
    $routes = require(__DIR__ . '/routes.php');
    $routes($app);
    return $app;
});

routes.php

<?php
use \Symfony\Component\HttpFoundation\Response;

return function(\Silex\Application $app) {
    $app->get('/', function() {
        return new Response('');
    });
};