Re: Documentation for custom-file - is not (load custom-file) needed?

[Luc Teirlinck]

Stefan Monnier wrote:

   You might be right.  It does seem however that the :get and :set functions
   don't need to do anything special.

The problem with setting the variable with setq instead of through
`custom-set-variables' is that various standard things like:

(put 'custom-file 'saved-value '("~/mycustomfile"))

and

(custom-push-theme 'theme-value 'custom-file 'user 'set '("~/mycustomfile"))

would not get done, unless you write them in .emacs.  But the things
you have to write into .emacs may change over time, because Custom may
change over time.  So you need a function that you have to update,
when needed.  There may be other problems we would have to think very
carefully about.  Why bother when `custom-set-variables' does
everything correctly for you?

The person using Custom to set an option should be able to rely on all
the features that customizing through Custom usually implies.  It is
OK if the user sets `custom-file' using setq in his .emacs, if the
user does not care about these features.  Those features are not
necessary (it would be a bug if they were), but they can be a
convenience.  I am talking about various things, customize-saved,
customize-customized, a correct "State" message in Custom buffers, as
well other things I can not immediately think of and possibly future
features.

Sincerely,

Luc.