anchor.diff:      : QUIT
       ;
   
  -BREAK
  +neww
  +    : (NEW1 | NEW2) SPACE* arglist
  +    ;
  +
  +breakk
  +    : (BREAK1 | BREAK2)
  +    ;
  +
  +BREAK1
       : B R E A K
  +    ;
  +
  +BREAK2
  +    : B
       ;
   
   CLOSE
  
positive.code:     : M E R G E
      ;
  
  NEW
      : N E W
      ;
  
  OPEN
  
negative.code:     : FOR SPACE+ term EQUALS term COLON term SPACE* (command SPACE?)* COLON (term (LT | GT) term)
      ;
  
  halt
      : (HALT1 | HALT2)
      ;
  
  write
      : (WRITE1 | WRITE2) SPACE* arglist
      ;
  