anchor.diff:  
   NOW : ('N'|'n')('O'|'o')('W'|'w');
   
  +UUID : ('U'|'u')('U'|'u')('I'|'i')('D'|'d');
  +
  +STRUUID : ('S'|'s')('T'|'t')('R'|'r')('U'|'u')('U'|'u')('I'|'i')('D'|'d');
  +
   MD5 : ('M'|'m')('D'|'d')'5';
   
   SHA1 : ('S'|'s')('H'|'h')('A'|'a')'1';
  
positive.code:     | '\u3001'..'\uD7FF'
      | '\uF900'..'\uFDCF'
      | '\uFDF0'..'\uFFFD'
      ;
  
  fragment
  PLX : PERCENT | PN_LOCAL_ESC;
  
  fragment
  
negative.code: LIMIT : ('L'|'l')('I'|'i')('M'|'m')('I'|'i')('T'|'t');
  
  OFFSET : ('O'|'o')('F'|'f')('F'|'f')('S'|'s')('E'|'e')('T'|'t');
  
  VALUES : ('V'|'v')('A'|'a')('L'|'l')('U'|'u')('U'|'u')('E'|'e')('E'|'e')('S'|'s')('S'|'s');
  
  OPTIONAL : ('O'|'o')('P'|'p')('T'|'t')('I'|'i')('O'|'o')('N'|'n')('A'|'a')('L'|'l');  
  
  