title: Grails: Call taglib from g:if tag
body: <p>I have a custom tag lib that returns a Boolean object so that my GSP can decide whether to display a piece of html or not.  I would like to use the g:if tag to check this Boolean's value since I also need to check a few other values (that aren't accesible in the taglib).  However, I don't know how to actually call the taglib from the  tag?</p>
  
  <p>I've tried:</p>
  
  <pre><code>&lt;g:if test="${&lt;custom:tag/&gt; &amp;&amp; other.boolean}"&gt;
  </code></pre>
  
  <p>but that throws errors.</p>
  
  <p>I also tried:</p>
  
  <pre><code>&lt;g:if test="&lt;custom:tag/&gt; &amp;&amp; ${other.boolean}"&gt;
  </code></pre>
  
  <p>but that throws errors too.</p>