title: How I can add String constant to xpath expression
body: <p>please help me in this problem.</p>
  
  <p>I have this xml:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;queries&gt;
          &lt;query&gt;
              &lt;name&gt;LOAD_ALL_DATA&lt;/name&gt;
              &lt;text&gt;[some query]&lt;/text&gt;
              &lt;key_fields&gt;
                  &lt;field&gt;
                      &lt;name&gt;login&lt;/name&gt;
                      &lt;db_table_name&gt;TABLE1_VIE&lt;/db_table_name&gt;
                      &lt;db_field_name&gt;LOGIN&lt;/db_field_name&gt;
                      &lt;owner&gt;User&lt;/owner&gt;
                  &lt;/field&gt;
                  &lt;field&gt;
                      &lt;name&gt;pass&lt;/name&gt;
                      &lt;db_table_name&gt;TABLE1_VIE&lt;/db_table_name&gt;
                      &lt;db_field_name&gt;PASS&lt;/db_field_name&gt;
                      &lt;owner&gt;User&lt;/owner&gt;
                  &lt;/field&gt;  
              &lt;/key_fields&gt;
          &lt;/query&gt;
      &lt;/queries&gt;
  </code></pre>
  
  <p>and this xpath expression, that returned some valuable values:</p>
  
  <pre><code>//queries/query[name = 'LOAD_ALL_DATA']/key_fields/field/name|
  //queries/query[name = 'LOAD_ALL_DATA']/key_fields/field/db_table_name |
  //queries/query[name = 'LOAD_ALL_DATA']/key_fields/field/db_field_name |
  //queries/query[name = 'LOAD_ALL_DATA']/key_fields/field/owner
  </code></pre>
  
  <p>for example, this expression returns this array:</p>
  
  <pre><code>login
  TABLE1_VIE
  LOGIN
  User
  pass
  TABLE1_VIE
  PASS
  User
  </code></pre>
  
  <p>Now i want to add name of node, that contain value, as in next example:</p>
  
  <pre><code>login/name
  TABLE1_VIE/db_table_name
  LOGIN/db_field_name
  User/owner
  pass/name
  TABLE1_VIE/db_table_name
  PASS/db_field_name
  User/owner
  </code></pre>
  
  <p>I tried to use function name(), but it doesn't work for me.</p>