element qualifier
open element namespace-modifier? (element-name | element-name-list) (of element-expression)?
 The element qualifier open element selects the current element or one of its ancestors using element-name, or by using the first name in element-name-list that matches the current element or
        one of its ancestors. If there is more than one opened element with the same name in the element stack of the
        currently-active parse, it will always refer to the innermost one.
      
 For example, in the following XML fragment, when parsing the innermost title element,
        
  <manual>
    <chapter>
      <title>First Chapter</title>
      <p>Introduction paragraph</p>
      <section id="S01.01">
        <title>First Section</title>
        <section id="S01.01.01">
          <title>Nested Section</title>
          ...
        </section>
        ...
      </section>
    </chapter>
  </manual>
          
        
 open element can refer to elements title, section,
        chapter, or manual. Additionally, when parsing the innermost title, the
        expression attribute "id" of open element "section" would evaluate to S01.01.01.