anchor.diff:  returns [StringBuilder text]
   @init {
       StringBuilder t = new StringBuilder();
  +    List<String> comps = new ArrayList<String>();
   }
   @after {
       $text = t;
  
positive.code: returns [StringBuilder text]
  @init {
      StringBuilder t = new StringBuilder();
  }
  @after {
      $text = t;
  
negative.code:                               }
                                     ( structureComponentDefinition 
                                     {
                                         comps.add( getText( $structureComponentDefinition.text ) );
                                     }
                                     )+
                                   )                          
                                {
                                    if ( sort ) sort( comps );
                                    t.append( cat( comps, false ) );
                                    indent--;
                                    t.append( getTab() + _END + _SPACE + _STRUCTURE );
                                }
  