title: Calling a macro inside another macro in Twig
body: <p>How <code>button_primary</code> macro can call <code>button</code> macro in Twig engine? I've tried 
   this solution, but it doesn't work, it says that <em>the function "button" does not exist</em>:</p>
  
  <pre><code>{% macro button(label, type, size) %}
      {% set type = type|default('default') %}
      {% set size = size|default('large') %}
      {% set cls = ['btn'] %}
  
      &lt;a href="#" class="{{ cls|join(' ') }}"&gt;{{ label }}&lt;/a&gt;
  {% endmacro %}
  
  {% macro button_primary(label, size) %}
      {{ button(label, 'primary', size) }}
  {% endmacro %}
  </code></pre>