bug#49689: [FEATURE REQUEST] Explicitly report change of input method

[Boruch Baum]

On 2021-07-22 09:11, Eli Zaretskii wrote:
> > Date: Wed, 21 Jul 2021 18:40:54 -0400
> > From: Boruch Baum <boruch_baum@gmx.com>
> >
> > Presently, a buffer's current input method is:
> >
> >   1] Only reported in the form of a cryptic symbol on the mode line.
>
> You get the full description if you hover the mouse pointer above that
> symbol (it's actually a short string).

Only in GUI emacs.

>  You can also do this:
>
>   M-: current-input-method RET

Not user-friendly or a form of automatic feedback.

> >   2] Aforementioned cryptic symbol is not guaranteed to be unique
> >      (BUG?).
>
> There are too few short meaningful strings to guarantee uniqueness.
> So, not a bug, but a mild misfeature due to screen estate constraints.
>
> >   2.1] Example: Hebrew and Hebrew-new

Hebrew-new could possibly be ח for חדש or ע with a unique diacritic.
Other Hebrew input methods use ע with diacritics and Hebrew-Lynx uses ל
instead of ע.

I haven't examined other cases of duplication, but my bet is that
scrutiny is likely to show that each can be uniquified.

> >
> > Please consider explicitly reporting changes to the input method. I've
> > done this to my personal satisfaction locally by adding a single line to
> > the end of each of functions `activate-input-method' and
> > `deactivate-input-method', both in file `mule-cmds'.
> >
> >   (message "Current input method is now: %s" current-input-method))
>
> I don't think I understand the feature request.  The message you
> suggest is ephemeral: it will be removed on the next keystroke.  So
> it's not like it will be shown there for prolonged periods of time.

That is the historical and current standard for emacs messaging. For
example, when one sets or un-sets a mode, emacs does just that, with
just the limitation to which you are objecting. The feature request can
be framed as asking for consistent emacs behavior to extend from changes
of mode to changes of input method.

> How will it help?

It would give immediate feedback upon change-of-state, similar to what
emacs does for many other changes of state, such as setting or
un-setting a mode.

>
> > This change has additional benefits:
> >
> >   1] Letting me know what I've done when I mis-type `C-\'.
>
> Doesn't "C-h l" help you know that?

Not user-friendly. Certainly not newbie-friendly.

> >
> >   2] Letting me know what to select when performing `C-h I'
>
> Please elaborate how does that message help with this last task.

It identifies the current input method by the exact (and guaranteed
unique) name that is used by the `C-h I' completing-read
completion-candidates collection.

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