[elisp] easy-to-use bookmarks functionality

[alex_sv]

Hi all,

For my own needs I wrote a small function that provides easy-to-use
bookmarking: C-[1..9] - sets "bookmark" (in fact remembers point in
the corresponding register), M-[1..9] - jumps to the corresponding
position.

Now I would like to see whether it could be implemented in a less
verbose and more intelligent way.

The flaws of my function are:
1) I don't know how to construct "key sequence" object from the
strings part, e.g. get "\C-1" sequence from the source strings "C-"
and "1", so I wrote local helper function - get-key-code that accepts
key sequence strings and creates the corresponding key sequence using
eval form with a call to kbd.
2) local-set-key function can't use locally defined closures so I
constructed corresponding lambda using append/list/quote facility that
looks quite ugly.

Here is the function:

(defun bind-navigation-command-to-numkeys ()
  "provides easy-to-use bookmarking functionality - binds navigation
commands to
C-{index}, M-{index} keys, where index is a numeric key from 1 to 9"
  (let (
        ;; helper function that returns key sequence object that
        ;; corresponds to the concatenated string sequence given
        (get-key-code (lambda (&rest key-sequence-str-list)
                        (eval (let ((key-sequence
                                     (mapconcat
                                      (function
                                       (lambda (c) c))
                                      key-sequence-str-list "")))
                                (append (list 'kbd)
                                        (list key-sequence)))))))
    ;; assign handlers for C/M-[1..9] keys
    (loop for key-index from 1 to 9 do
          (let ((key-str (int-to-string key-index)))
            ;; save point
            (local-set-key (funcall get-key-code "C-" key-str)
                           ;; handler form
                           (list 'lambda '()
                                 '(interactive)
                                 (list 'point-to-register key-index)))
            ;; goto saved point
            (local-set-key (funcall get-key-code "M-" key-str)
                           ;; handler form
                           (list 'lambda '()
                                 '(interactive)
                                 (list 'register-to-point key-index)))))))

comments appreciated :)