anchor.diff:  protected XML_COMMENT_END : "-->" ;
   protected XML_PI_START : "<?" ;
   protected XML_PI_END : "?>" ;
  +protected XML_CDATA_START : "<![CDATA[";
  +protected XML_CDATA_END : "]]>";
   
   protected LETTER
   :
  
positive.code: 	( XML_PI_START )
  	=> XML_PI { $setType(XML_PI); }
  	|
  	END_TAG_START
  	{
  		inElementContent= false;
  
negative.code: 	xmlComment 
  	| 
  	xmlPI
  	|
  	cdataSection
  	;
  
  computedConstructor throws XPathException
  