bug#50801: 28.0.50; Emacs manual about file variables doesn't mention that major modes shouldn't end in "-mode"

bug#50801: 28.0.50; Emacs manual about file variables doesn't mention that major modes shouldn't end in "-mode"

[Daniel Martín via Bug reports for GNU Emacs, the Swiss army knife of text editors]

I'm reviewing the manuals for the upcoming Emacs 28 and I have a couple
of minor suggestions for node "49.2.4.1 Specifying File Variables":

The node doesn't explictly mention the crucial information that in
'mode: MODENAME' 'MODENAME' must not end in "-mode".  It's true that
there's an example down there that says "mode: Lisp", so users may infer
that you don't need to spell the major mode with "-mode", but I thought
it may be better to be explicit about in the manual.

Another suggestion I have is that the manual doesn't mention that
something like "-*- C++ -*-" (that is, omitting the "mode" keyword) is
also supported.  Many free software projects have traditionally been
using "-* C++ -*" in their C++ header files to make Emacs distinguish
them from plain C files.  See also src/epaths.in in the Emacs
repository, among others.  I see this used by Jim Blandy since 1992 at
least, but I don't really know if a) it's really a stable way to declare
a file-local mode, and we may lack the historical info to answer that,
and b) it's worth mentioning it in the manual.

Thanks.

bug#50801: 28.0.50; Emacs manual about file variables doesn't mention that major modes shouldn't end in "-mode"

[Stefan Kangas]

Daniel Martín <mardani29@yahoo.es> writes:

> I'm reviewing the manuals for the upcoming Emacs 28 and I have a couple
> of minor suggestions for node "49.2.4.1 Specifying File Variables":

That is extremely useful, thank you very much for working on this.

(BTW, you can press `w' in info to get a reference like "(emacs)
Specifying File Variables".  This is not super important, but a handy
feature to know about, as you can then `M-: (info "...")' and get to
that section quickly.)

> The node doesn't explictly mention the crucial information that in
> 'mode: MODENAME' 'MODENAME' must not end in "-mode".  It's true that
> there's an example down there that says "mode: Lisp", so users may infer
> that you don't need to spell the major mode with "-mode", but I thought
> it may be better to be explicit about in the manual.

Fully agreed.  Perhaps something like this?

diff --git a/doc/emacs/custom.texi b/doc/emacs/custom.texi
index d12033f841..d5f18fff35 100644
--- a/doc/emacs/custom.texi
+++ b/doc/emacs/custom.texi
@@ -1084,8 +1084,9 @@ Specifying File Variables
 @noindent
 You can specify any number of variable/value pairs in this way, each
 pair with a colon and semicolon.  The special variable/value pair
-@code{mode: @var{modename};}, if present, specifies a major mode.  The
-@var{value}s are used literally, and not evaluated.
+@code{mode: @var{modename};}, if present, specifies a major mode
+(excluding the ``-mode'' part).  The @var{value}s are used literally,
+and not evaluated.

 @findex add-file-local-variable-prop-line
 @findex delete-file-local-variable-prop-line

> Another suggestion I have is that the manual doesn't mention that
> something like "-*- C++ -*-" (that is, omitting the "mode" keyword) is
> also supported.  Many free software projects have traditionally been
> using "-* C++ -*" in their C++ header files to make Emacs distinguish
> them from plain C files.  See also src/epaths.in in the Emacs
> repository, among others.  I see this used by Jim Blandy since 1992 at
> least, but I don't really know if a) it's really a stable way to declare
> a file-local mode, and we may lack the historical info to answer that,
> and b) it's worth mentioning it in the manual.

I can't remember the details, but I believe that this form is considered
obsolete and/or problematic.  So I think it's fine to not document it.

bug#50801: 28.0.50; Emacs manual about file variables doesn't mention that major modes shouldn't end in "-mode"

[Daniel Martín via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Stefan Kangas <stefan@marxist.se> writes:

>
>> I'm reviewing the manuals for the upcoming Emacs 28 and I have a couple
>> of minor suggestions for node "49.2.4.1 Specifying File Variables":
>
> That is extremely useful, thank you very much for working on this.
>
> (BTW, you can press `w' in info to get a reference like "(emacs)
> Specifying File Variables".  This is not super important, but a handy
> feature to know about, as you can then `M-: (info "...")' and get to
> that section quickly.)

Yep, I forgot to add a direct link to the Info node, sorry.  BTW you can
'C-u w' to get the link inside a function call to `info` directly.

>
>> The node doesn't explictly mention the crucial information that in
>> 'mode: MODENAME' 'MODENAME' must not end in "-mode".  It's true that
>> there's an example down there that says "mode: Lisp", so users may infer
>> that you don't need to spell the major mode with "-mode", but I thought
>> it may be better to be explicit about in the manual.
>
> Fully agreed.  Perhaps something like this?
>
> diff --git a/doc/emacs/custom.texi b/doc/emacs/custom.texi
> index d12033f841..d5f18fff35 100644
> --- a/doc/emacs/custom.texi
> +++ b/doc/emacs/custom.texi
> @@ -1084,8 +1084,9 @@ Specifying File Variables
>  @noindent
>  You can specify any number of variable/value pairs in this way, each
>  pair with a colon and semicolon.  The special variable/value pair
> -@code{mode: @var{modename};}, if present, specifies a major mode.  The
> -@var{value}s are used literally, and not evaluated.
> +@code{mode: @var{modename};}, if present, specifies a major mode
> +(excluding the ``-mode'' part).  The @var{value}s are used literally,
> +and not evaluated.

I'm not a native speaker but it reads well to me, thank you.

>
>  @findex add-file-local-variable-prop-line
>  @findex delete-file-local-variable-prop-line
>
>> Another suggestion I have is that the manual doesn't mention that
>> something like "-*- C++ -*-" (that is, omitting the "mode" keyword) is
>> also supported.  Many free software projects have traditionally been
>> using "-* C++ -*" in their C++ header files to make Emacs distinguish
>> them from plain C files.  See also src/epaths.in in the Emacs
>> repository, among others.  I see this used by Jim Blandy since 1992 at
>> least, but I don't really know if a) it's really a stable way to declare
>> a file-local mode, and we may lack the historical info to answer that,
>> and b) it's worth mentioning it in the manual.
>
> I can't remember the details, but I believe that this form is considered
> obsolete and/or problematic.  So I think it's fine to not document it.

Makes sense.

bug#50801: 28.0.50; Emacs manual about file variables doesn't mention that major modes shouldn't end in "-mode"

[Lars Ingebrigtsen]

Stefan Kangas <stefan@marxist.se> writes:

> -@code{mode: @var{modename};}, if present, specifies a major mode.  The
> -@var{value}s are used literally, and not evaluated.
> +@code{mode: @var{modename};}, if present, specifies a major mode
> +(excluding the ``-mode'' part).  The @var{value}s are used literally,
> +and not evaluated.

Makes sense to me.

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

bug#50801: 28.0.50; Emacs manual about file variables doesn't mention that major modes shouldn't end in "-mode"

[Andreas Schwab]

On Sep 25 2021, Stefan Kangas wrote:

> diff --git a/doc/emacs/custom.texi b/doc/emacs/custom.texi
> index d12033f841..d5f18fff35 100644
> --- a/doc/emacs/custom.texi
> +++ b/doc/emacs/custom.texi
> @@ -1084,8 +1084,9 @@ Specifying File Variables
>  @noindent
>  You can specify any number of variable/value pairs in this way, each
>  pair with a colon and semicolon.  The special variable/value pair
> -@code{mode: @var{modename};}, if present, specifies a major mode.  The
> -@var{value}s are used literally, and not evaluated.
> +@code{mode: @var{modename};}, if present, specifies a major mode
> +(excluding the ``-mode'' part).  The @var{value}s are used literally,

without the ``-mode'' suffix

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."

bug#50801: 28.0.50; Emacs manual about file variables doesn't mention that major modes shouldn't end in "-mode"

[Stefan Kangas]

tags 50801 fixed
close 50801 28.1
thanks

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Stefan Kangas <stefan@marxist.se> writes:
>
>> -@code{mode: @var{modename};}, if present, specifies a major mode.  The
>> -@var{value}s are used literally, and not evaluated.
>> +@code{mode: @var{modename};}, if present, specifies a major mode
>> +(excluding the ``-mode'' part).  The @var{value}s are used literally,
>> +and not evaluated.
>
> Makes sense to me.

Thanks, I have now made this change on master (commit 68994995db) with
the improvement suggested by Andreas.

I'm therefore closing this bug report.

bug#50801: 28.0.50; Emacs manual about file variables doesn't mention that major modes shouldn't end in "-mode"

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

  > > +@code{mode: @var{modename};}, if present, specifies a major mode
  > > +(excluding the ``-mode'' part).  The @var{value}s are used literally,

  > without the ``-mode'' suffix

Indeed.  `-mode' is NOT part of the mode's name.  The name of Mail
mode, which I'm using now, is "Mail", not "Mail mode".

-- 
Dr Richard Stallman (https://stallman.org)
Chief GNUisance of the GNU Project (https://gnu.org)
Founder, Free Software Foundation (https://fsf.org)
Internet Hall-of-Famer (https://internethalloffame.org)