anchor.diff:  
   triplesSameSubjectPath
       : ^(TRIPLES_SAME_SUBJECT ^(SUBJECT varOrTerm) propertyListNotEmpty)
  -    | ^(TRIPLES_SAME_SUBJECT  triplesNode (^(SUBJECT BLANK_NODE) propertyListNotEmpty)?)
  +    | ^(TRIPLES_SAME_SUBJECT  triplesNode propertyListNotEmpty?)
       ;
       
   path
  
positive.code:     ;
  
  whereClause
      : ^(WHERE_CLAUSE groupGraphPattern)
      ;
      
  solutionModifier
  
negative.code:     ;
  
  subSelect
      : ^(SUBSELECT whereClause* datasetClause* solutionModifier)
      ;
      	
  selectClause
  