anchor.diff:      ;
   
   quit_
  -    : (QUIT | 'Q') term
  +    : (QUIT) term
       ;
   
   new_
  -    : (NEW | 'N') SPACE* arglist
  +    : (NEW) SPACE* arglist
       ;
   
   break_
  -    : (BREAK | 'B')
  +    : (BREAK)
       ;
   
   do_
  -    : (DO | 'D') SPACE* identifier (LPAREN paramlist? RPAREN)?
  +    : (DO) SPACE* identifier (LPAREN paramlist? RPAREN)?
       ;
   
   BREAK
  
positive.code:     ;
  
  set_
      : (SET | 'S') SPACE+ assign (',' assign)*
      ;
  
  assign
  
negative.code:     ;
  
  for_
      : FOR SPACE+ term EQUALS term COLON term SPACE* (command SPACE?)* COLON SPACE* condition
      ;
  
  halt_
      : (HALT)
      ;
  
  hang_
  