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:     ;   
      
  load 	  
      : ^(LOAD SILENT* iriRef graphRef*)
      ;
      
  clear
  
negative.code:     | ^(IRI expression)
      | ^(URI expression)
      | ^(BNODE expression)
      | BNODE
      | RAND
      | ^(ABS expression)
      | ^(CEIL expression)
  