twig で再帰処理 ref: http://qiita.com/nanasess/items/5a1a6dbc1090e8ec0b36

file0.txt

        {% macro recursiveCategories(Category) %}
            {% if Category.hasChildNodes() %}
                <ul>
                    {% for child in Category.childNodes() %}
                        <li>{{ child.name }}</li>
                        {{ _self.recursiveCategories(child) }}
                    {% endfor %}
                </ul>
            {% endif %}
        {% endmacro %}
        {% if Category.hasChildNodes() %}
        <ul>
            {% for ChildCategory in Category.childNodes() %}         
                <li>{{ ChildCategory.name }}</li>
                {{ _self.recursiveCategories(ChildCategory) }}         
            {% endfor %}
        </ul>
        {% endif %}