anchor.diff:  (defun validate-operation-def-change (def &key 
                                               (mode (op:mode def))
                                               (result (op:result_def def))
  -                                            (params (op:params def))
  +                                            (params (slot-value def 'params))
                                               (exceptions (op:exceptions def)))
     (validate-operation-def mode result params exceptions))
   
  
positive.code: 
  ;;;  WstringDef create_wstring (in unsigned long bound);
  
  ;;;  SequenceDef create_sequence
  ;;;     (in unsigned long bound,in IDLType element_type);
  
  
negative.code: 
  (defun validate-operation-def (mode result params exceptions)
    (when (eq mode :op_oneway)
      (unless (and (eq :tk_void (op:kind (op:type result)))
                   (zerop (length exceptions))
                   (every (lambda (p)
                            (eq :param_in (op:mode p)))
  