Expose Slim urlFor to Twig

index.php

<?php
// Wrapper function to access urlFor.
function slim_url_for($name, $params = array()) {
	return Slim::getInstance()->urlFor($name, $params);
}

// Setup Twig.
TwigView::$twigDirectory =  '/path/to/twig/';

// Expose urlFor to Twig.
$view = new TwigView;
$twig = $view->getEnvironment();
$twig->addFunction('url', new Twig_Function_Function('slim_url_for'));

// Setup Slim.
$app = new Slim(array('view' => new TwigView));

// Create a named route.
$app->get('/article/(:id)', function($id) {
    // Your logic here.
})->name('article_view');

/* 
 * In your templates you can now the following code to generate the URL:
 * {{ url('article_view', { 'id': article.id }) }}
 */