bug#13276: 24.2.50; apropos-variable

["Drew Adams" <drew.adams@oracle.com>]

> >> I suggest renaming `apropos-variable' to `apropos-option' and to
> >> use `apropos-variable' for 
> > That sounds right.
> The attached patch does this.

Glad to see this finally happening.

> It renames `apropos-variable' to `apropos-option' and define a new
> `apropos-variable' command.  C-u M-x apropos-variable RET shows only
> user options, and C-u M-x apropos-option RET shows all variables.
> 
> The patch also introduces a new button for user options so that
> users can immediately see which variables are options in the apropos
> buffer.

IOW, essentially the code I pointed to last month (as well as years ago):
http://www.emacswiki.org/emacs/download/apropos-fn%2bvar.el


FWIW, this doc line is not too good:

 With \\[universal-argument] prefix, or if `apropos-do-all' is non-nil, also
show
-normal variables."
+variables, not just user options."

User options _are_ variables.  The line should say something like "also show
variables that are not user options."


Question (not particularly related to this patch):

Why do we treat the faces differently for, say, `apropos-symbol' and
`apropos-variable'?

apropos.el defines faces for these buttons:

apropos-function-button
apropos-variable-button
apropos-option-button
apropos-misc-button

But it defines faces for these things - not for their buttons:

apropos-symbol
apropos-keybinding
apropos-property

Why don't we handle the following the same way we handle `apropos-symbol' (or
vice versa):

apropos-function
apropos-variable
apropos-option
apropos-misc

E.g., when defining their button types, just include both `button' and the
thing's face for property `face'?  E.g.,

(defface apropos-option '((t (:inherit font-lock-variable-name-face)))
  "Face used for option names in Apropos buffers."
  :group 'apropos)

(define-button-type 'apropos-option
  'apropos-label "Option"
  'apropos-short-label "o"
  'face '(apropos-option button)  ; <======================
  'help-echo "mouse-2, RET: Display more help on this user option (variable)"
  'follow-link t
  'action (lambda (button)
            (describe-variable (button-get button 'apropos-symbol))))

Just wondering.  Why do we treat these differently?  In all cases the faces are
used only for buttons.  Is there some advantage to using one or the other
treatment?  Thx.