anchor.diff:                         (buffer-minor-modes))
                    (keymap-find-keybind (mode-keymap (buffer-major-mode)) key)
                    (keymap-find-keybind *global-keymap* key))))
  -    (function-to-command cmd)))
  +    (function-to-command (or cmd 'undefined-key))))
  
positive.code: (define-key *global-keymap* "C-@" 'undefined-key)
  (define-key *global-keymap* "C-a" 'undefined-key)
  (define-key *global-keymap* "C-b" 'undefined-key)
  (define-key *global-keymap* "C-c" 'undefined-key)
  (define-key *global-keymap* "C-d" 'undefined-key)
  (define-key *global-keymap* "C-e" 'undefined-key)
  (define-key *global-keymap* "C-f" 'undefined-key)
  
negative.code:      (kbd-keys (cons string-or-first-key keys)))))
  
  (defun keymap-find-keybind (keymap key)
    (let ((keymap0 keymap))
      (labels ((f (k)
                  (let ((cmd (gethash k (keymap-table keymap))))
                    (if (keymap-p cmd)
                        (setf keymap cmd)
                        cmd))))
        (or (if (kbd-p key)
                (let (cmd)
                  (dolist (k (kbd-list key) cmd)
                    (setf cmd (f k))))
                (f key))
            (let ((parent (keymap-parent keymap0)))
              (when parent
                (keymap-find-keybind parent key)))
            (keymap-undef-hook keymap0)))))
  
  (defun search-keybind-all (name)
    (let ((name (intern (string-upcase name) :lem))
  