anchor.diff:      ;
   
   prologue
  +    /* The tree rewriting rule, as used here, implicitely induces a sorting order */
       : (baseDecl | prefixDecl)* -> ^(PROLOGUE baseDecl* prefixDecl*)
       ;
   
   baseDecl
       : BASE IRI_REF -> ^(BASE IRI_REF)
  -    ;
  +    ; 
   
   prefixDecl
       : PREFIX PNAME_NS IRI_REF -> ^(PREFIX PNAME_NS IRI_REF)
  
positive.code:     ;
      
  iriRefOrFunction
      : iriRef 
      | iriRef argList -> ^(FUNCTION iriRef ^(ARG_LIST argList))
      ;
  
  rdfLiteral
  
negative.code: 	
  triplesNode
      : OPEN_BRACE graphNode+ CLOSE_BRACE -> ^(COLLECTION graphNode+)
      | OPEN_SQUARE_BRACKET propertyListNotEmpty CLOSE_SQUARE_BRACKET -> ^(TRIPLES_NODE propertyListNotEmpty)
      ;
  
  graphNode
  