anchor.diff:      : FOR SPACE+ term EQUALS term COLON term SPACE* (command SPACE?)* COLON (term (LT | GT) term)
       ;
   
  +write
  +    : (WRITE1 | WRITE2) SPACE* arglist
  +    ;
  +
  +quit
  +    : QUIT
  +    ;
  +
   BREAK
       : B R E A K
       ;
  
positive.code:     ;
  
  set
      : SET SPACE+ assign (',' assign)*
      ;
  
  assign
  
negative.code:     ;
  
  commandname
      : (BREAK | CLOSE | DO | ELSE | GOTO | HALT | HANG | IF | JOB
        | KILL | LOCK | MERGE | NEW | OPEN | READ | TCOMMIT
        | TRESTART | TROLLBACK | TSTART | USE | VIEW| XECUTE)
        | set 
        | form
        | write
        | quit
      ;
  
  arglist
  