Re: Shrinking the C core

[Eli Zaretskii]

> From: Richard Stallman <rms@gnu.org>
> Cc: emacs-devel@gnu.org
> Date: Sun, 10 Sep 2023 20:43:01 -0400
> 
> The cl libraries of Emacs Lisp define functions that are not standard
> parts of Emacs Lisp.  They are not documented in the Emacs Lisp
> Reference Manual -- for good reason (we don't want to write that
> documentation or have a commitment to maintain ever after later).  As
> a consequence, code which uses those constructs is extra work to
> understand and to maintain.

This particular aspect -- documentation -- is somewhat blurred these
days: you will find some "cl-*" functions in the ELisp manual.
(Typing "i cl- TAB" in the ELisp manual produces 5 completion
candidates.)  So we do document some cl functions when we find that
useful.

> If you want to use them in your own private code, that's no problem
> for anyone else -- do what you feel like, there.  Using them in a
> not-terribly-vital package that you maintain and some others use is
> not a big drawback.  However, using them in code others need to
> maintain makes maintaining Emacs harder.
> 
> I do not say "impossible", but it is worth avoiding.

This message is in many cases met with opposition and thus is not easy
to send in practice.