bug#53776: Modeline indicator when using define-minor-mode

[Stephen Berman <stephen.berman@gmx.net>]

On Fri, 04 Feb 2022 13:22:08 +0000 goncholden <goncholden@protonmail.com> wrote:

> ------- Original Message -------
>
> On Friday, February 4th, 2022 at 1:02 PM, Stephen Berman
> <stephen.berman@gmx.net> wrote:
>
>> On Fri, 04 Feb 2022 11:55:45 +0000 goncholden via "Bug reports for GNU
>> Emacs, the Swiss army knife of text editors" bug-gnu-emacs@gnu.org wrote:
>>
>> > Have been using define-minor-mode and noticed that when setting the
>> > modeline indicator, the text is appended with no space between other
>> > modeline indicators. Is this how :lighter is supposed to work?
>>
>> Yes, the lack of a space is in the definition of `mode-line-modes':`
>> (:propertize ("" minor-mode-alist)
>>
>> I guess the reason is that you can have multiple minor mode lighters and
>> providing a space between each would complicate the definition of
>> `mode-line-modes', so that's the job of the minor mode definition
>> itself:
>>
>> > (define-minor-mode rich-minor-mode
>> >
>> > "This is the docstring."
>> > :lighter "rich"
>>
>> So you should do this: :lighter " rich"
>>
>> Steve Berman
>
> Because one can easily add minor-modes that exceed the mode-line mini-buffer,
> is there
> the capability of making a hierarchical modeline indicator.
>
> e.g.
>
> Emacs-Lisp
> company
> Outl
> Gon -> rich
>     -> gudin
>     -> cholden

That would appear to require a multiline mode line, which is not
possible with the current implementation.  An alternative, which might
be easier to implement (for someone who knows how, not me), would be to
make the mode line horizontally scrollable.  But maybe that's not so
easy, since it seems so obviously useful, yet hasn't been implemented.

Steve Berman