Re: Learning Edebug

[Eduardo Ochs <eduardoochs@gmail.com>]

On Fri, 20 Dec 2024 at 00:15, Lewis Creary via Users list for the GNU
Emacs text editor <help-gnu-emacs@gnu.org> wrote:
>
> Hello,
>
> I'm trying to learn how to use the Emacs lisp function Edebug, but
> so far am not having any success.  The documentation says that I
> need to "instrument" the function that I want to debug, and I'm even
> having trouble with that.
>
> I've been programming in Emacs Lisp for over a decade, and have
> always found that print statements were sufficient for debugging my
> programs.  But now I have a bug that I won't be able to
> understand without stepping through the code with a debugger --
> hence the need for Edebug.  I'm looking for a person who is
> willing and able to help me learn to use this tool.  If you are
> such a person, I'd be very glad to hear from you.


Hi Lewis,

this is a mini-tutorial on Edebug that I wrote for a friend some time
ago:

--snip--snip--
;; Preparation:
;;   (emacs-lisp-mode)
;;   (require 'edebug)
;;
;; See: (find-elinode "edebug")
;;      (find-elnode "Edebug")
;;      (find-efunctiondescr 'eval-defun "instrument")
;;      (find-efunctiondescr 'edebug-mode)
;;      (find-efunctiondescr 'edebug-mode "C-M-x" "eval-defun")
;;      (eek "M-h M-k  M-C-x  ;; eval-defun")
;;
(defun ee-triangle-buggy (n)
  (if (= n 1) 1
    (+ n (ee-triangle-buggy (1= n)))))

;; Instrument the defun above with:   (eek "3*<up> C-u M-C-x")
;; Run it in edebug mode with:        (ee-triangle-buggy 4)
;; Start by learning these keys:
;;      (find-elnode "Edebug Execution Modes" "<SPC>" "Step:")
;;      (find-elnode "Edebug Misc" "q" "Return to the top level")
--snip--snip--

It needs eev, and it uses elisp hyperlinks. Everything there should
make sense to people who understand the sections 2 and 3 of the main
tutorial of eev - see:

  Trying eev with a sexp (2024)
  http://anggtwu.net/2024-find-tryit-links.html

Usually Brazilians understand eev immediately, but for many people in
developed countries using explicit sexps feels so wrong that examples
like the one above don't make any sense at all, even after years. I
talked a bit about that in my presentation at the EmacsConf2024 and in
a related video. Here are links to their subtitles:

  http://anggtwu.net/emacsconf2024.html#0:00
  http://anggtwu.net/2024-bash-test-blocks.html#0:00

My holidays have just started and I am planning to hang out a lot in
the #emacs IRC channel in the next days. If you would like to chat
meet me there or send me an e-mail!

  Cheers,
    Eduardo Ochs
    http://anggtwu.net/#eev