anchor.diff:  // lexer rules --------------------------------------------------------------------------------
   
   // keywords
  +ABORT : A B O R T;
   ACCEPT : A C C E P T;
   ACCESS : A C C E S S;
   ADD : A D D;
  
positive.code: OPTIONAL : O P T I O N A L;
  OR : O R;
  ORDER : O R D E R;
  ORGANIZATION : O R G A N I Z A T I O N;
  OTHER : O T H E R;
  OUTPUT : O U T P U T;
  
negative.code: CLASS : C L A S S;
  CLOCK_UNITS : C L O C K MINUSCHAR U N I T S;
  CLOSE : C L O S E;
  CLOSE_DISPOSITION : C L O S E MINUSCHAR D I S P O S I T I O N;
  COBOL : C O B O L;
  CODE : C O D E;
  CODEPAGE : C O D E P A G E;
  