<?php
class Gettext_Twig_Extension extends Twig_Extension
{
   public function getFilters()
   {
        return array(
            't' => new Twig_Filter_Function('gettext'),
        );
   }
}
/*
$twig = new Twig_Environment(...);
$twig->addExtension('Gettext_Twig_Extension.class.php');
{{ 'MY_USERNAME'|t }} can now be used in templates to display the gettext string associated with the "MY_USERNAME" key.
*/