Re: autoload cookies for defcustoms

[Lennart Borgman <lennart.borgman@gmail.com>]

On Sat, Jan 23, 2010 at 7:31 PM, Drew Adams <drew.adams@oracle.com> wrote:
> Just curious. Is there a policy, for the Lisp code distributed with Emacs, about
> using autoload cookies for defcustoms? If so, what is it?


We had a discussion about that in November:

  http://lists.gnu.org/archive/html/emacs-devel/2009-11/msg00504.html

The conclusion there was that all defcustoms (~7000) can't be
autoloaded but that we can probably set it up so that completion of
options knows all option names (and maybe apropos can know about them
too).

But we did not finish that. I think I have some more things to test
there, but anyone who want to join is of course wellcome.


> Looking through the code, it seems that most defcustoms are not autoloaded, but
> some are. And in the same library some might be and others not.
>
> Some use `purecopy' for their values, so I guess it makes sense to autoload
> those. But it's not clear which came first, the cookie or the decision to use
> `purecopy'.
>
> If, in some library, only the options that use `purecopy' are autoloaded,
> doesn't that give a misleading impression to users of `C-h v'? They see only the
> `purecopy' ones (before loading), which aren't necessarily the most important to
> know about.
>
> IOW, are there two conflicting criteria for autoloading an option: (1) its
> importance or frequency of use or the need for users to know about it before
> loading vs (2) the purely technical (implementation) criterion of its use of
> `purecopy'. Shouldn't the only criterion be use- and user-centered (i.e., #1)?
>
> Some options that do not use `purecopy' are nevertheless autoloaded. And some
> that do use `purecopy' do not have an autoload cookie - e.g.,
> `epa-file-name-regexp', `automount-dir-prefix', `directory-free-space-program',
> `search-whitespace-regexp', `jka-compr-load-suffixes', `rmail-file-name',
> `site-run-file', `initial-scratch-message', `vc-directory-exclusion-list',
> `adaptive-fill-regexp', `adaptive-fill-first-line-regexp'. (Is that wrong, or
> are all of those libraries always preloaded?)
>
> If there is no general policy, and this is decided individually for each
> defcustom, then just what considerations affect the judgment? And why is there
> such variability among libraries?
>
> The same question could apply to command definitions, but there there doesn't
> seem to be such a difference among libraries for them. Most commands seem to
> have autoload cookies (just as most options do not), and I'm guessing that those
> commands that do not are considered to be less often used.
>
>
>
>