bug#38601: describe-mode never says the most important thing

[Phil Sainty <psainty@orcon.net.nz>]

On 16/12/19 11:00 AM, Tomas Nordin wrote:
> Phil Sainty <psainty@orcon.net.nz> writes:
>> (I do think there's an argument for showing the mode symbol rather
>> than a capitalised variant of the name in the `describe-mode' help;
>> but that's a different conversation.)
>
> A different conversation but I didn't see that so I take the
> opportunity to agree here. The capitalized variants of the command
> name was always confusing to me -- is it the command name, only
> with a big letter in the beginning, or is it some sort of doxy
> description that is not the same as the command name. Easy to check,
> but anyway.

For the major mode it's just the `mode-name' value.

For the minor modes it's the symbol name, sans "-minor-mode"/"-mode",
passed through `capitalize': "foo-bar-mode" becomes "Foo-Bar".

This is hard-coded in `describe-mode', which produces the following:

(pp-eval-expression
 '(let (minor-modes)
    ;; Older packages do not register in minor-mode-list but only in
    ;; minor-mode-alist.
    (dolist (x minor-mode-alist)
      (setq x (car x))
      (unless (memq x minor-mode-list)
        (push x minor-mode-list)))
    ;; Find enabled minor mode we will want to mention.
    (dolist (mode minor-mode-list)
      ;; Document a minor mode if it is listed in minor-mode-alist,
      ;; non-nil, and has a function definition.
      (let ((fmode (or (get mode :minor-mode-function) mode)))
        (and (boundp mode) (symbol-value mode)
             (fboundp fmode)
             (let ((pretty-minor-mode
                    (if (string-match "\\(\\(-minor\\)?-mode\\)?\\'"
                                      (symbol-name fmode))
                        (capitalize
                         (substring (symbol-name fmode)
                                    0 (match-beginning 0)))
                      fmode)))
               (push (list fmode pretty-minor-mode
                           (format-mode-line
                             (assq mode minor-mode-alist)))
                     minor-modes)))))
    minor-modes))