bug#24780: 26.0.50; describe-mode lexical-binding

bug#24780: 26.0.50; describe-mode lexical-binding

[Andreas Röhler]

Hi,

consider it useful if `describe-mode' reports value of var 
`lexical-binding'.
Even displaying it in mode-line might be an option.

Thanks,
Andreas


In GNU Emacs 26.0.50.1 (i686-pc-linux-gnu, GTK+ Version 3.14.5)
  of 2016-10-11

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bug#24780: 26.0.50; describe-mode lexical-binding

[Alan Mackenzie]

Hello, Lars.

In article <mailman.2389.1564232406.2688.bug-gnu-emacs@gnu.org> you wrote:
> Andreas Röhler <andreas.roehler@easy-emacs.de> writes:

>> consider it useful if `describe-mode' reports value of var
>> `lexical-binding'.

> Hm...  That command describes the mode, and whether the current .el file
> uses lexical binding or not isn't really tied to the mode, so I think
> that sounds a bit confusing.  The user may believe that we're talking
> about whether the mode uses lexical binding or not.

>> Even displaying it in mode-line might be an option.

> That does sound more useful -- I often find jumping back to the start of
> the buffer to check.

> `emacs-lisp-mode' could display that somewhere in the mode line, I
> guess?  But where?  Perhaps among the U:**- thing at the start?  Or in
> the mode stuff?

> So instead of

> (Emacs-Lisp)

> we'd get

> (Emacs-Lisp Lexical)

> when we have lexical binding in the current buffer?  Does anybody have
> an opinion here?

Yes.  "Lexical" is too long, considering its relative lack of
importance.  Space on the mode line is precious, particularly when
running Follow Mode.  Also, "Lexical" isn't really a minor mode, so
shouldn't look like one.

How about, instead,

    (Emacs-Lisp/L)

or

    (Emacs-Lisp/D)

?  Even that is going to be a nuisance to some people, so it really
needs a user option to turn it off.

> -- 
> (domestic pets only, the antidote for overdose, milk.)
>    bloggy blog: http://lars.ingebrigtsen.no

-- 
Alan Mackenzie (Nuremberg, Germany).

bug#24780: 26.0.50; describe-mode lexical-binding

[Stefan Kangas]

Alan Mackenzie <acm@muc.de> writes:

>> Andreas Röhler <andreas.roehler@easy-emacs.de> writes:
>
>>> consider it useful if `describe-mode' reports value of var
>>> `lexical-binding'.
[...]
>>> Even displaying it in mode-line might be an option.
>
>> That does sound more useful -- I often find jumping back to the start of
>> the buffer to check.
>
>> `emacs-lisp-mode' could display that somewhere in the mode line, I
>> guess?  But where?  Perhaps among the U:**- thing at the start?  Or in
>> the mode stuff?
>
>> So instead of
>
>> (Emacs-Lisp)
>
>> we'd get
>
>> (Emacs-Lisp Lexical)
>
>> when we have lexical binding in the current buffer?  Does anybody have
>> an opinion here?
>
> Yes.  "Lexical" is too long, considering its relative lack of
> importance.  Space on the mode line is precious, particularly when
> running Follow Mode.  Also, "Lexical" isn't really a minor mode, so
> shouldn't look like one.
>
> How about, instead,
>
>     (Emacs-Lisp/L)
>
> or
>
>     (Emacs-Lisp/D)

How about:

     (Emacs-Lisp)

And:

     (Emacs-Lisp/D)

This would indicate the legacy nature of dynamic binding, and gently
nudge users to move to lexical-binding.

> ?  Even that is going to be a nuisance to some people, so it really
> needs a user option to turn it off.

I wouldn't add a user option.  The correct way to get rid of the "/D",
if it bothers you, would then be to convert the code to
lexical-binding.

Best regards,
Stefan Kangas

bug#24780: 26.0.50; describe-mode lexical-binding

[Lars Ingebrigtsen]

Stefan Kangas <stefan@marxist.se> writes:

> How about:
>
>      (Emacs-Lisp)
>
> And:
>
>      (Emacs-Lisp/D)
>
> This would indicate the legacy nature of dynamic binding, and gently
> nudge users to move to lexical-binding.

That's a very good idea, I think.

>> ?  Even that is going to be a nuisance to some people, so it really
>> needs a user option to turn it off.
>
> I wouldn't add a user option.  The correct way to get rid of the "/D",
> if it bothers you, would then be to convert the code to
> lexical-binding.

Heh heh.  Nice.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#24780: 26.0.50; describe-mode lexical-binding

[Lars Ingebrigtsen]

Lars Ingebrigtsen <larsi@gnus.org> writes:

>> This would indicate the legacy nature of dynamic binding, and gently
>> nudge users to move to lexical-binding.
>
> That's a very good idea, I think.

Heh.  I should look at the mode line more -- it currently says "Elisp/l"
and "Elisp/d" with a ugly orange on the "/d", so I guess somebody
already fixed this without us noticing?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#24780: 26.0.50; describe-mode lexical-binding

[Stefan Kangas]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Lars Ingebrigtsen <larsi@gnus.org> writes:
>
>>> This would indicate the legacy nature of dynamic binding, and gently
>>> nudge users to move to lexical-binding.
>>
>> That's a very good idea, I think.
>
> Heh.  I should look at the mode line more -- it currently says "Elisp/l"
> and "Elisp/d" with a ugly orange on the "/d", so I guess somebody
> already fixed this without us noticing?

I missed that due to diminish, which changes it to "el" for me in both
cases.  But you are correct now that I'm trying emacs -Q.

This was added in:

commit 620f672518b1c009a028ebdb0fd1d4a0aabfa1d0
Author: Stefan Monnier <monnier@iro.umontreal.ca>
Date:   Tue Mar 3 11:34:49 2020 -0500

    * lisp/progmodes/elisp-mode.el (elisp-enable-lexical-binding): New command

    (emacs-lisp-mode): Indicate lex/dyn binding mode in the mode line.
    (elisp--dynlex-modeline-map): New var.

We could of course still change it to "Elisp" for the "Elisp/l" case.
Or we could just close this bug.

Best regards,
Stefan Kangas

bug#24780: 26.0.50; describe-mode lexical-binding

[Lars Ingebrigtsen]

Stefan Kangas <stefan@marxist.se> writes:

> We could of course still change it to "Elisp" for the "Elisp/l" case.
> Or we could just close this bug.

I think "Elisp/l" is fine (for the time being; we can remove the "/l" in
some years).

So I've already closed the bug.  :-)

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#24780: 26.0.50; describe-mode lexical-binding

[Stefan Kangas]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Stefan Kangas <stefan@marxist.se> writes:
>
>> We could of course still change it to "Elisp" for the "Elisp/l" case.
>> Or we could just close this bug.
>
> I think "Elisp/l" is fine (for the time being; we can remove the "/l" in
> some years).
>
> So I've already closed the bug.  :-)

Sounds good, thanks.

bug#24780: 26.0.50; describe-mode lexical-binding

[Lars Ingebrigtsen]

Andreas Röhler <andreas.roehler@easy-emacs.de> writes:

> consider it useful if `describe-mode' reports value of var
> `lexical-binding'.

Hm...  That command describes the mode, and whether the current .el file
uses lexical binding or not isn't really tied to the mode, so I think
that sounds a bit confusing.  The user may believe that we're talking
about whether the mode uses lexical binding or not.

> Even displaying it in mode-line might be an option.

That does sound more useful -- I often find jumping back to the start of
the buffer to check.

`emacs-lisp-mode' could display that somewhere in the mode line, I
guess?  But where?  Perhaps among the U:**- thing at the start?  Or in
the mode stuff?

So instead of

(Emacs-Lisp)

we'd get

(Emacs-Lisp Lexical)

when we have lexical binding in the current buffer?  Does anybody have
an opinion here?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#24780: 26.0.50; describe-mode lexical-binding

[Noam Postavsky]

Lars Ingebrigtsen <larsi@gnus.org> writes:

>> Even displaying it in mode-line might be an option.
>
> That does sound more useful -- I often find jumping back to the start of
> the buffer to check.

> (Emacs-Lisp Lexical)
>
> when we have lexical binding in the current buffer?  Does anybody have
> an opinion here?

IMO it's not worth spending space on the mode line for this.  Yeah,
sometimes I want to check, and M-< followed by C-u C-SPC to go back
works fine for that.

bug#24780: 26.0.50; describe-mode lexical-binding

[Lars Ingebrigtsen]

Noam Postavsky <npostavs@gmail.com> writes:

> IMO it's not worth spending space on the mode line for this.  Yeah,
> sometimes I want to check, and M-< followed by C-u C-SPC to go back
> works fine for that.

OK, there doesn't seem to be much enthusiasm for putting this in our
precious mode line real estate, and I concur.

But I had another look at `describe-mode', and contrary to what I
believed, it does include stuff that's not directly mode-related.  In
particular:

	;; Narrowing is not a minor mode, but its indicator is part of
	;; mode-line-modes.
	(when (buffer-narrowed-p)
	  (push '(narrow-to-region "Narrow" " Narrow") minor-modes))

So perhaps it'd be an idea to do the same with `lexical-binding'?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#24780: 26.0.50; describe-mode lexical-binding

[Drew Adams]

> >> Even displaying it in mode-line might be an option.
> >
> > That does sound more useful -- I often find jumping back to the start
> > of the buffer to check.
> 
> > (Emacs-Lisp Lexical)
> >
> > when we have lexical binding in the current buffer?  Does anybody
> > have an opinion here?
> 
> IMO it's not worth spending space on the mode line for this.  Yeah,
> sometimes I want to check, and M-< followed by C-u C-SPC to go back
> works fine for that.

+10.  YAGNI.

Emacs itself should avoid adding more stuff to the
mode line.  It should be conservative about that.

In addition to `M-< C-u C-SPC', it's trivial and
quick to do `C-h v lex TAB'.