anchor.diff:  
   subsequentArcIdentifier : '/' arcIdentifier subsequentArcIdentifier | ;
   
  -arcIdentifier: integerUnicodeLabel | nonintegerUnicodeLabel ;
  +arcIdentifier: INTEGERUNICODELABEL | NONINTEGERUNICODELABEL ;
   
   xMLIRIValue: firstArcIdentifier subsequentArcIdentifier ;
   
  
positive.code: 
  simpleTableConstraint: objectSet ;
  
  componentRelationConstraint: '{' definedObjectSet '}' '{' atNotation (',' atNotation)* '}' ;
  
  atNotation: '@' componentIdList | '@' '.' level componentIdList ;
  
  
negative.code: XMLHEX: [0-9A-Fa-f] ;
  CSTRINGCHAR: ~[\"] ;
  XMLCHARACTER: [\x09\x10\x13\x0020-\xD7FF\xE000-\xFFFD\x010000-\x10FFFF] ;
  XMLCHARCODES: '&#' NUMBER* ';' ;
  XMLCHARHEXCODES: '&#x' XMLHEX* ';' ;
  XMLCHARAMPCODES: '&amp;' | '&lt;' | '&gt;' ;
  XMLCHARXMLCODES
  	: '<nul/>' | '<soh/>' | '<stx/>' | '<etx/>' | '<eot/>' | '<enq/>' | '<ack/>' | '<bel/>' | '<bs/>'
  