Re: Advantage using mapc over dolist

[Tomas Hlavaty <tom@logand.com>]

On Tue 03 Dec 2024 at 22:24, Jean Louis <bugs@gnu.support> wrote:
>> > I am an Emacs Lisp programmer, and all Common Lisp functions
>> > prefixed with `cl-` I find liberating in the sense that personally
>> > within Emacs Lisp I do not like mixing it because it is not Common Lisp.

Maybe the issue is that too many things were degraded into cl-*.
And now very complex bad ideas are pushed as replacement fix.

>> > But within Emacs, I like using Emacs Lisp pure

Not sure what does "Emacs Lisp pure" mean.
Does it mean "Whatever comes with Emacs except cl-* stuff."?

"Emacs Lisp pure" had CASE and ECASE in 1993 (conversion to RCS
according to git) until 2012 iirc.

> But Tomas, I mentioned nothing about pcase. I said cl- namespace being
> separate feels liberating to me as my personal choice. If you wish to
> use those commands without cl-prefix, there is solution that Stefan
> wrote in recent email.

Bad workarounds do not fill me with joy.

>> Anytime I process complex
>> data recursively, I reach for labels.  There does not seem to be an
>> alternative, does it? 
>
> I have no idea about it, let me see what AI says:

That AI is not good enough.
The examples are too trivial to justify labels.

This function has a structure which does justify labels:

(defun parse-rss (dom)
  (let (z)
    (cl-labels ((link (x)
                  (when (consp x)
                    (cl-case (car x)
                      (link (push (caddr x) z))
                      (t (mapc #'link (cddr x))))))
                (rec (x)
                  (when (consp x)
                    (cl-case (car x)
                      (item (link x))
                      (t (mapc #'rec (cddr x)))))))
      (rec dom))
    (nreverse z)))

> So I would say, I would not get frustrated, rather just make an alias
> for me and use `labels' wherever I wish and want.

This does not address the problem.

In my Elisp code, I simply require cl-lib, add those cl- prefixes where
needed and live with the result.

However, here simple and likely pre-CL functions and macros are degraded
to cl-*, people are discouraged from using cl-* and encouraged to use
something even more bonkers than cl-* ;-)