anchor.diff:  (defmacro sort-values (pred &rest values)
     "Sort VALUES with PRED and return as multiple values.
   
  -Equivalent to 
  +Equivalent to
   
       (values-list (sort (list VALUES...) pred))
   
  
positive.code:   (with-gensyms (temp)
      `(let ((,temp (make-array ,(length values))))
         (declare (dynamic-extent ,temp))
         ,@(loop for i from 0 
                 for v in values
                 collect `(setf (svref ,temp ,i) ,v))
         ;; Keep compiler quiet.
  
negative.code: (defmacro ecase-let ((var expr) &body cases)
    "Like (let ((VAR EXPR)) (ecase VAR ...)), with VAR read-only."
    `(let1 ,var ,expr
       (ecase ,var
         ,@cases)))
  
  (defmacro comment (&body body)
  