anchor.diff:             :isearch-prev
              :isearch-yank
              :isearch-self-insert
  +           :isearch-replace-highlight
  +           :isearch-next-highlight
  +           :isearch-prev-highlight
  +           :isearch-toggle-highlighting
              :read-query-replace-args
              :isearch-toggle-highlighting
              :query-replace
  
positive.code: (defun isearch-update-minibuffer ()
    (message-without-log "~A~A" *isearch-prompt* *isearch-string*))
  
  (define-command isearch-forward () ()
    (isearch-start
     "ISearch: "
     (lambda (point str)
       (search-forward (or (character-offset point (- (length str)))
                           point)
  
negative.code:    #'search-backward
     ""))
  
  (define-command isearch-backward (&optional prompt) ((list nil))
    (isearch-start
     (or prompt "ISearch: ")
     (lambda (point str)
       (search-backward (or (character-offset point (length str))
                            point)
  