anchor.diff:  returns [StringBuilder text]
   @init {
       StringBuilder t = new StringBuilder();
  +    List<String> halfRels = new ArrayList<String>();
   }
   @after {
       $text = t;
  
positive.code: returns [StringBuilder text]
  @init {
      StringBuilder t = new StringBuilder();
  }
  @after {
      $text = t;
  
negative.code:                                    }
                                     ( transitionRow          
                                     {
                                         rows.add( getText( $transitionRow.text ) );
                                     }
                                     )+
                                     {
  