anchor.diff:  
   fragment
   ECHAR
  -    : '\\' ('t' | 'b' | 'n' | 'r' | 'f' | '"' | '\'')
  +    : '\\' ('t' | 'b' | 'n' | 'r' | 'f' | '\\' | '"' | '\'')
       ;
   
   fragment
  
positive.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
   *
   */
  
  
negative.code:     : MINUS DOUBLE
      ;
  
  fragment
  EXPONENT
      : ('e'|'E') (PLUS|MINUS)? DIGIT+
      ;
  