(defun format-error (string &rest args)     ;Example 
       (error nil "~?~%~V@T!~%~3@T\"~A\"~%" 
              string args (+ *ctl-index* 3) *ctl-string*))

##</code><code>##

  (format stream
          ;; Are you ready for this one?
          "~:[{~;[~]~:{~S~:[->~S~;~*~]~:^ ~}~:[~; ~]~
           ~{~S->~^ ~}~:[~; ~]~[~*~;->~S~;->~*~]~:[}~;]~]"
          ;; Is that clear?
          ;; I omitted the sprintf-style arguments here - MJD
  )