anchor.diff:  
   fragment
   EOL
  -    : '\n'| '\r'
  +    : '\n' | '\r'
       ;
   
   REFERENCE
  
positive.code:     : MINUS DOUBLE
      ;
  
  EXPONENT
      : ('e'|'E') (PLUS|MINUS)? DIGIT+
      ;
  
negative.code:  * Simone Tripodi,21.11.2007 Replaced parser literal IRI_REF by lexer tokens as preparation for AST generation
   * Jrgen Pfundt, 25.11.2007 The A token is case insensitive now as requested by the w3.org rdf-sparql-query
   *                           document
   * Jrgen Pfundt, 18.01.2008 Made EXPONENT a fragment.
   *                           Added missing backslash to fragment ECHAR as defined by the w3.org rdf-sparql-query
   *                           document.
   *
   */
  
  