title: Groovy XmlSlurper: get value of attribute that has an associated namespace
body: <p>I have an XML document that contains attributes with qualified names. I want to get the attribute value using XmlSlurper, but trying to access the attribute without specifying the namespace does not work (below is a minimal example).</p>
  
  <pre class="lang-groovy prettyprint-override"><code>def rootNode = new XmlSlurper().parseText(
  '''&lt;root xmlns:ex="http://example.com"&gt;
       &lt;one ex:a1="uno!"/&gt;
       &lt;ex:two&gt;Some text!&lt;/ex:two&gt;
     &lt;/root&gt;''' )
  
  assert rootNode.one[0].@a1.text() == 'uno!'
  </code></pre>
  
  <p><code>rootNode.one[0].@a1.text()</code> will yield an empty string. If using <code>rootNode.one[0].'@ex:a1'.text()</code> we get the correct value, but this is dependent on the namespace prefix used in the document - and that can't be relied upon to be the same for other documents, the associated namespace is what matters.</p>
  
  <p><strong>So the question is:</strong>
  How can XmlSlurper be used to access an attribute value of an attribute that has an associated namespace without the need to specify the namespace prefix?
  (it would be OK if supplying the whole namespace is needed)</p>