bug#12199: c-guess doesn't guess indent-tabs-mode

bug#12199: c-guess doesn't guess indent-tabs-mode

[Johan Walles]

Package: emacs
Version: 24.1.1

Hi Emacsers!

c-guess seems not to guess the correct value for indent-tabs-mode.

Try this:
1. Set indent-tabs-mode to nil.
2. Load a C file indented with tabs.
3. c-guess
4. Do describe-variable on indent-tabs-mode

Current result:
"Its value is nil"

Expected result:
"Its value is t" (since c-guess should have noticed that tabs are used
for indentation)

Note:
In my case this makes c-guess much less useful than it could have
been, since I work on both tab and space indented files.

  Regards //Johan

bug#12199: c-guess doesn't guess indent-tabs-mode

[Stefan Kangas]

found 12199 26.1
thanks

Johan Walles <johan.walles@gmail.com> writes:

> Package: emacs
> Version: 24.1.1
>
> Hi Emacsers!
>
> c-guess seems not to guess the correct value for indent-tabs-mode.
>
> Try this:
> 1. Set indent-tabs-mode to nil.
> 2. Load a C file indented with tabs.
> 3. c-guess
> 4. Do describe-variable on indent-tabs-mode
>
> Current result:
> "Its value is nil"
>
> Expected result:
> "Its value is t" (since c-guess should have noticed that tabs are used
> for indentation)
>
> Note:
> In my case this makes c-guess much less useful than it could have
> been, since I work on both tab and space indented files.
>
>   Regards //Johan

I can reproduce this on Emacs 26.1.  I'm not sure if this is a bug or a
feature request.

Best regards,
Stefan Kangas

bug#12199: c-guess doesn't guess indent-tabs-mode

[Lars Ingebrigtsen]

[-- Attachment #1: Type: text/plain, Size: 587 bytes --]

Johan Walles <johan.walles@gmail.com> writes:

> Try this:
> 1. Set indent-tabs-mode to nil.
> 2. Load a C file indented with tabs.
> 3. c-guess
> 4. Do describe-variable on indent-tabs-mode
>
> Current result:
> "Its value is nil"
>
> Expected result:
> "Its value is t" (since c-guess should have noticed that tabs are used
> for indentation)

This still seems to be the case in Emacs 28.

I've included my test file here.  Perhaps Alan has some insights here?
(Added to the CCs.)

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

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: indent.c --]
[-- Type: text/x-csrc, Size: 28 bytes --]

main () {
	foo();
	bar();
}

bug#12199: c-guess doesn't guess indent-tabs-mode

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Tue, 01 Jun 2021 09:35:19 +0200
> Cc: Alan Mackenzie <acm@muc.de>, 12199@debbugs.gnu.org
> 
> > Try this:
> > 1. Set indent-tabs-mode to nil.
> > 2. Load a C file indented with tabs.
> > 3. c-guess
> > 4. Do describe-variable on indent-tabs-mode
> >
> > Current result:
> > "Its value is nil"
> >
> > Expected result:
> > "Its value is t" (since c-guess should have noticed that tabs are used
> > for indentation)
> 
> This still seems to be the case in Emacs 28.
> 
> I've included my test file here.  Perhaps Alan has some insights here?
> (Added to the CCs.)

AFAICT, c-guess.el doesn't try to guess the value of indent-tabs-mode,
it only guesses indentation parameters specific to CC Mode.

IOW, this feature, if it belongs to c-guess.el, was never implemented.

bug#12199: c-guess doesn't guess indent-tabs-mode

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

> AFAICT, c-guess.el doesn't try to guess the value of indent-tabs-mode,
> it only guesses indentation parameters specific to CC Mode.

Ah, right.  And looking more closely at that file, it doesn't talk about
indent-tabs-mode at all, so I guess this bug report it mistaken.  (But
as you say, it could possibly be a new feature.)

But c-guess works as documented here, I'm closing this bug report.

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