Symfony 2.3中的表单字段属性

It was possible in Symfony 2.2 to access form field attributes in template this way:

<?php $form['field_name']->get('field_attribute') ?>

How can i do this in Symfony 2.3? FormView object doesn't have this function any more.

Edit :

Indeed the FormView no longers has get function instead you have :

array $vars The variables assigned to this view. 

The similar in twig : {{ form.task.vars.full_name }}

The PHP snippet on the documentation seems outdated