title: XSLT: Sum of specific attribute value based on other attribute's name
body: <p>I have the following XML document (provided by a different party)</p>
  
  <pre><code>&lt;transactions&gt;
    &lt;transaction TaxAType="11" TaxAValue="111" TaxBType="2" TaxBValue="222" TaxCType="3" TaxCValue="333"/&gt;
    &lt;transaction TaxAType="11" TaxAValue="111" TaxBType="2" TaxBValue="222" TaxCType="3" TaxCValue="333"/&gt;
  &lt;/transactions&gt;
  </code></pre>
  
  <p>I would like to write an XSLT document that would transform these lines and sum up the Tax*Value if the corresponding Tax*Type = '11' for example.</p>
  
  <p>Is this something possible without using a template?</p>
  
  <p>name(), substring(), etc. functions in the XQuery?
  What are your thoughts on this?</p>