bug#67848: 29.1; Fix usage of `setq-default' and add explanation

bug#67848: 29.1; Fix usage of `setq-default' and add explanation

[Xiyue Deng]

In the lisp intro book, there is a discrepancy in the section "Text and
Auto Fill mode" where the first code example uses "(setq-default
major-mode 'text-mode)"[1] but in the later explanation part the
function was changed to `setq'[2].  It looks like the original change[3]
was to deprecate the usage of "default-major-mode", but forgot to update
the other part.

I have prepared a patch to make it consistent, and also added some extra
text to explain why `setq-default' is required for a buffer local
variable using a foot note.  Will add in the next mail.

[1] https://git.savannah.gnu.org/cgit/emacs.git/tree/doc/lispintro/emacs-lisp-intro.texi#n16902
[2] https://git.savannah.gnu.org/cgit/emacs.git/tree/doc/lispintro/emacs-lisp-intro.texi#n16946
[3] https://git.savannah.gnu.org/cgit/emacs.git/commit/?id=cd61af01c1220b6a7f98189c826edc7535416583



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bug#67848: 29.1; Fix usage of `setq-default' and add explanation

[Xiyue Deng]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: 0001-Fix-usage-of-setq-default-and-add-explanation-bug-67.patch --]
[-- Type: text/x-diff, Size: 1903 bytes --]

From 197467583063492dee7bc2fc40709ecb3a3d17e9 Mon Sep 17 00:00:00 2001
From: Xiyue Deng <manphiz@gmail.com>
Date: Sat, 16 Dec 2023 02:06:15 -0800
Subject: [PATCH] Fix usage of `setq-default' and add explanation (bug#67848)

cd61af0 changed from default-major-mode to major-mode in the first
code sample but didn't change the rest.  Fix it here and add some
explanations of why use `setq-default' instead of `setq'.

* doc/lispintro/emacs-lisp-intro.texi (Text and Auto-fill): fix `setq'
to `setq-default' and add some explanations.
---
 doc/lispintro/emacs-lisp-intro.texi | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/doc/lispintro/emacs-lisp-intro.texi b/doc/lispintro/emacs-lisp-intro.texi
index eb8ff413b79..2468571eb96 100644
--- a/doc/lispintro/emacs-lisp-intro.texi
+++ b/doc/lispintro/emacs-lisp-intro.texi
@@ -16943,14 +16943,19 @@ Here is the line again; how does it work?
 
 @cindex Text Mode turned on
 @smallexample
-(setq major-mode 'text-mode)
+(setq-default major-mode 'text-mode)
 @end smallexample
 
 @noindent
 This line is a short, but complete Emacs Lisp expression.
 
-We are already familiar with @code{setq}.  It sets the following variable,
-@code{major-mode}, to the subsequent value, which is @code{text-mode}.
+We are already familiar with @code{setq}.  We use a similar macro
+@code{setq-default} to set the following variable,
+@code{major-mode}@footnote{We use @code{setq-default} because
+@code{text-mode} is buffer local.  If we use @code{setq} it will only
+apply to the current buffer, and using @code{setq-default} will also
+apply this to newly created buffers.}, to the subsequent value, which is
+@code{text-mode}.
 The single-quote before @code{text-mode} tells Emacs to deal directly
 with the @code{text-mode} symbol, not with whatever it might stand for.
 @xref{set & setq, , Setting the Value of a Variable},
-- 
2.39.2

bug#67848: 29.1; Fix usage of `setq-default' and add explanation

[Eli Zaretskii]

> From: Xiyue Deng <manphiz@gmail.com>
> Date: Sat, 16 Dec 2023 03:18:20 -0800
> 
> 
> In the lisp intro book, there is a discrepancy in the section "Text and
> Auto Fill mode" where the first code example uses "(setq-default
> major-mode 'text-mode)"[1] but in the later explanation part the
> function was changed to `setq'[2].  It looks like the original change[3]
> was to deprecate the usage of "default-major-mode", but forgot to update
> the other part.
> 
> I have prepared a patch to make it consistent, and also added some extra
> text to explain why `setq-default' is required for a buffer local
> variable using a foot note.  Will add in the next mail.

Thanks, but I think it's wrong to use setq-default here, since that
makes Text mode the default major-mode (instead of Fundamental), which
is not what most people would want.

I think we should instead do one of the following:

  . convert the _first_ setq-default to setq
  . do as above, and also explain that people who really want Emacs to
    start new buffers in Text mode should use setq-default

Would you like to amend your patch along these lines?

bug#67848: 29.1; Fix usage of `setq-default' and add explanation

[Xiyue Deng]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Xiyue Deng <manphiz@gmail.com>
>> Date: Sat, 16 Dec 2023 03:18:20 -0800
>> 
>> 
>> In the lisp intro book, there is a discrepancy in the section "Text and
>> Auto Fill mode" where the first code example uses "(setq-default
>> major-mode 'text-mode)"[1] but in the later explanation part the
>> function was changed to `setq'[2].  It looks like the original change[3]
>> was to deprecate the usage of "default-major-mode", but forgot to update
>> the other part.
>> 
>> I have prepared a patch to make it consistent, and also added some extra
>> text to explain why `setq-default' is required for a buffer local
>> variable using a foot note.  Will add in the next mail.
>
> Thanks, but I think it's wrong to use setq-default here, since that
> makes Text mode the default major-mode (instead of Fundamental), which
> is not what most people would want.

Actually making text-mode the default mode for new files is exactly what
the author intended based on the text from an earlier section[1].  In
addition, the previous change was to deprecate `default-major-mode'
which used to achieve the same effect.  So it looks like that the
intention to change the default major-mode for new files is consistent
through the text.

Of course, whether this is a good advice is a slightly different matter,
and may be worth discussing in a footnote if it sounds worth doing.  But
based on the text flow setting the new default major-mode should not be
changed IMHO.

>
> I think we should instead do one of the following:
>
>   . convert the _first_ setq-default to setq
>   . do as above, and also explain that people who really want Emacs to
>     start new buffers in Text mode should use setq-default
>
> Would you like to amend your patch along these lines?

[1] https://git.savannah.gnu.org/cgit/emacs.git/tree/doc/lispintro/emacs-lisp-intro.texi#n16569

-- 
Xiyue Deng

bug#67848: 29.1; Fix usage of `setq-default' and add explanation

[Eli Zaretskii]

> From: Xiyue Deng <manphiz@gmail.com>
> Cc: 67848@debbugs.gnu.org
> Date: Sat, 23 Dec 2023 02:09:29 -0800
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> From: Xiyue Deng <manphiz@gmail.com>
> >> Date: Sat, 16 Dec 2023 03:18:20 -0800
> >> 
> >> 
> > Thanks, but I think it's wrong to use setq-default here, since that
> > makes Text mode the default major-mode (instead of Fundamental), which
> > is not what most people would want.
> 
> Actually making text-mode the default mode for new files is exactly what
> the author intended based on the text from an earlier section[1].

I know, but I don't want that to be said without reservations, or not
at all.  The author's hope was that there will be many readers of this
manual who are not programmers, and who would then prefer Text mode as
the default.  We are now a few decades wiser, and we know that hope
didn't really materialize.  So we should not advertise such a setting
without some explanations.

> Of course, whether this is a good advice is a slightly different matter,
> and may be worth discussing in a footnote if it sounds worth doing.  But
> based on the text flow setting the new default major-mode should not be
> changed IMHO.

Sorry, I disagree, for the reasons explained above.

Thanks.

bug#67848: 29.1; Fix usage of `setq-default' and add explanation

[Xiyue Deng]

[-- Attachment #1: Type: text/plain, Size: 1694 bytes --]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Xiyue Deng <manphiz@gmail.com>
>> Cc: 67848@debbugs.gnu.org
>> Date: Sat, 23 Dec 2023 02:09:29 -0800
>> 
>> Eli Zaretskii <eliz@gnu.org> writes:
>> 
>> >> From: Xiyue Deng <manphiz@gmail.com>
>> >> Date: Sat, 16 Dec 2023 03:18:20 -0800
>> >> 
>> >> 
>> > Thanks, but I think it's wrong to use setq-default here, since that
>> > makes Text mode the default major-mode (instead of Fundamental), which
>> > is not what most people would want.
>> 
>> Actually making text-mode the default mode for new files is exactly what
>> the author intended based on the text from an earlier section[1].
>
> I know, but I don't want that to be said without reservations, or not
> at all.  The author's hope was that there will be many readers of this
> manual who are not programmers, and who would then prefer Text mode as
> the default.  We are now a few decades wiser, and we know that hope
> didn't really materialize.  So we should not advertise such a setting
> without some explanations.

While I kind of agree with what you said here, this requires a much
larger rewrite of the text, because there are several paragraphs that
span several sections that follows the author's original advice of
making newly opened files to use text-mode instead of fundamental mode
by default.  Neither being a writer, nor even a native English speaker,
I don't consider myself a good candidate to make such a drastic change
to this classic book.

So instead I added another footnote at the first sentence of this
section to suggest that the suggestion was aimed for writers and the
reader can feel free not to do this.  The new patch is attached.  PTAL.

-- 
Xiyue Deng


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From d5e89a19ee7fcfe2aa6bb35f5ad84eb17819408b Mon Sep 17 00:00:00 2001
From: Xiyue Deng <manphiz@gmail.com>
Date: Sat, 23 Dec 2023 16:12:44 -0800
Subject: [PATCH] Fix usage of `setq-default' and offer more suggestions

cd61af0 changed from default-major-mode to major-mode in the first
code sample but didn't change the rest.  This patch fixes this and add
some explanations of why use `setq-default' instead of `setq'.  In
addition, it gives background on suggesting using text-mode as default
mode and suggest other alternatives.

* doc/lispintro/emacs-lisp-intro.texi (Text and Auto-fill): Fix usage
of `setq-default' and offer more suggestions.  (Bug#67848)
---
 doc/lispintro/emacs-lisp-intro.texi | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/doc/lispintro/emacs-lisp-intro.texi b/doc/lispintro/emacs-lisp-intro.texi
index 4a0e8dfa1fc..26a405361de 100644
--- a/doc/lispintro/emacs-lisp-intro.texi
+++ b/doc/lispintro/emacs-lisp-intro.texi
@@ -16892,8 +16892,12 @@ remember to look here to remind myself.
 @node Text and Auto-fill
 @section Text and Auto Fill Mode
 
-Now we come to the part that turns on Text mode and
-Auto Fill mode.
+Now we come to the part that turns on Text mode and Auto Fill
+mode.@footnote{This section suggests settings that are more suitable
+for writers.  For programmers, the default mode will be set to the
+corresponding prog-mode automatically based on the type of the file.
+And it's perfectly fine if you want to keep the fundamental mode as
+the default mode.}
 
 @smallexample
 @group
@@ -16945,15 +16949,19 @@ Here is the line again; how does it work?
 
 @cindex Text Mode turned on
 @smallexample
-(setq major-mode 'text-mode)
+(setq-default major-mode 'text-mode)
 @end smallexample
 
 @noindent
 This line is a short, but complete Emacs Lisp expression.
 
-We are already familiar with @code{setq}.  It sets the following
-variable, @code{major-mode}, to the subsequent value, which is
-@code{text-mode}.  The single-quote before @code{text-mode} tells
+We are already familiar with @code{setq}.  We use a similar macro
+@code{setq-default} to set the following variable,
+@code{major-mode}@footnote{We use @code{setq-default} because
+@code{text-mode} is buffer local.  If we use @code{setq} it will only
+apply to the current buffer, and using @code{setq-default} will also
+apply this to newly created buffers.}, to the subsequent value, which
+is @code{text-mode}.  The single-quote before @code{text-mode} tells
 Emacs to deal directly with the @code{text-mode} symbol, not with
 whatever it might stand for.  @xref{setq, , Setting the Value of
 a Variable}, for a reminder of how @code{setq} works.  The main point
-- 
2.39.2

bug#67848: 29.1; Fix usage of `setq-default' and add explanation

[Eli Zaretskii]

> From: Xiyue Deng <manphiz@gmail.com>
> Cc: 67848@debbugs.gnu.org
> Date: Sat, 23 Dec 2023 23:00:59 -0800
> 
> While I kind of agree with what you said here, this requires a much
> larger rewrite of the text, because there are several paragraphs that
> span several sections that follows the author's original advice of
> making newly opened files to use text-mode instead of fundamental mode
> by default.  Neither being a writer, nor even a native English speaker,
> I don't consider myself a good candidate to make such a drastic change
> to this classic book.
> 
> So instead I added another footnote at the first sentence of this
> section to suggest that the suggestion was aimed for writers and the
> reader can feel free not to do this.  The new patch is attached.  PTAL.

Thanks, installed on the emacs-29 branch, and closing the bug.