anchor.diff:  ;; to avoid having CMUCL treat it as a constant, in which case
   ;; code under the false branch would be optimized away!
   (defvar SpecCalc::specwareWizard? nil) ; see Specware4/Languages/SpecCalculus/Semantics/Monad.sw
  +
  +;;; CEM: 2014-04-30  
  +;;; This is safer than trying to make sure there is only one instance of '(:|None|).
  +;;; For example, what mapvec::*undefined* does.
  +(defun undefined? (val)
  +  (and (listp val)
  +       (null (cdr val))
  +       (eq (car val) ':|None|)))
   
   (defparameter quotient-tag
     (list :|Quotient|))
  
positive.code:     ;; that we must respect fill pointers.
      (vector
       (macrolet ((frob ()
                    '(let ((result 572539))
                       (declare (type fixnum result))
                       (mixf result (length key))
                      (when (plusp depthoid)
                        (decf depthoid)
                        (dotimes (i (length key))
                         (declare (type fixnum i))
                         (mixf result
                               (swxhash (aref key i) depthoid))))
  
negative.code:                                                   (v-equal t (slang-term-equals-2 (svref t1 i)  (svref t2 i))))
                                                   ((or (= i mindim) (not v-equal)) v-equal)
                                                 (declare (fixnum i)))
                                               ;; second, the extension must consist solely of undefined values
                                               (if (eql mindim dim1)
                                                   ;; t2 is longer
                                                   (do ((i dim1 (+ i 1))
                                                        (v-equal t (undefined? (svref t2 i))))
                                                       ((or (= i dim2) (not v-equal)) v-equal)
                                                     (declare (fixnum i)))
                                                   ;; t1 is longer
                                                   (do ((i dim2 (+ i 1))
                                                        (v-equal t (undefined? (svref t1 i))))
                                                       ((or (= i dim1) (not v-equal)) v-equal)
                                                     (declare (fixnum i))))))))))))
                   (t (equalp t1 t2))
  