anchor.diff:      ;
   
   triplesSameSubject
  -    : varOrTerm propertyListNotEmpty -> ^(TRIPLES_SAME_SUBJECT ^(SUBJECT varOrTerm) propertyListNotEmpty)
  +    : varOrTerm propertyListNotEmpty? -> ^(TRIPLES_SAME_SUBJECT ^(SUBJECT varOrTerm) propertyListNotEmpty?)
       | triplesNode propertyListNotEmpty? -> ^(TRIPLES_SAME_SUBJECT triplesNode (^(SUBJECT BLANK_NODE) propertyListNotEmpty)?) 
       ;
   
  
positive.code:     ;
  
  subSelect
      : selectClause whereClause solutionModifier	-> ^(SUBSELECT whereClause* solutionModifier)
      ;
      	
  selectClause
  
negative.code: 
  NOW : ('N'|'n')('O'|'o')('W'|'w');
  
  MD5 : ('M'|'m')('D'|'d')'5';
  
  SHA1 : ('S'|'s')('H'|'h')('A'|'a')'1';
  
  