code: public function XSLT($filepath, $use_xslcache = true)
      {
          if ($use_xslcache && extension_loaded('xslcache')) {
              $xslt = new XSLTCache;
              $xslt->importStylesheet($filepath);
          } else {
              $xsl = new DOMDocument;
              $xsl->load($filepath);
  
              $xslt = new XSLTProcessor;
              $xslt->importStylesheet($xsl);
          }
  
          return $xslt->transformToXML(dom_import_simplexml($this));
      }
docs: Transform current node and return the result
  
  Will take advantage of {@link http://pecl.php.net/package/xslcache PECL's xslcache}
  if available
  
  @param    string $filepath Path to stylesheet
  @param    bool $use_xslcache If TRUE, use the XSL Cache extension if available
  @return    string                    Result