| ``empty`` | |
| ========= | |
| ``empty`` checks if a variable is an empty string, an empty array, an empty | |
| hash, exactly ``false``, or exactly ``null``. | |
| For objects that implement the ``Countable`` interface, ``empty`` will check the | |
| return value of the ``count()`` method. | |
| For objects that implement the ``__toString()`` magic method (and not ``Countable``), | |
| it will check if an empty string is returned. | |
| .. code-block:: twig | |
| {% if foo is empty %} | |
| ... | |
| {% endif %} | |