Re: Let mode-line packages distinguish the selected-window

[Jonas Bernoulli <jonas@bernoul.li>]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> To deal with this the packages mentioned above resort to using several
>> hook functions and advice to keep track of "the" selected window and
>> then they do something like:
>
> AFAIK since Emacs-24.4 only one hook is needed:

Well it seems I (or any of the maintainers of the other packages,
really) should have asked a bit earlier.  oO

>> Because keeping remembered-selected-window up-to-date involves several
>> hooks and advises this is rather ugly and fragile.
>
> With `pre-redisplay-function(s)` is should be "easy and reliable".

That's very promising indeed.  The minibuffer window needs to be handled
a bit differently, I think:

    (defun moody--set-active-window (_)
      (let ((win (selected-window)))
        (unless (minibuffer-window-active-p win)
          (setq moody--active-window win))))

    (add-hook 'pre-redisplay-functions #'moody--set-active-window)

>> In summary, please add a way for functions that format elements of the
>> mode-line to determine whether these elements are going to be used in
>> the selected or some other window.
>
> Despite what the above may suggest, I fully agree: while it's now easy
> to "roll your own", this is a common need and we should provide this
> info directly.

That would be nice. (And no Eli, I don't have a patch ready.  Not much
of a C guy.  Not at all really.)

But even though I suggested something like that, I feel the
remembered-selected-window approach is a bit hackish.  IMO it would be
nicer if instead of that variable regular selected-window would return
"that window" while a new function/variable named something like
mode-line-window returned the "window whose mode-line is currently being
updated".  But that would be a breaking change, so maybe not.

  Jonas