bug#67158: [PATCH] Repair tab-always-indent

[Aymeric Agon-Rambosson <aymeric.agon@yandex.com>]

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Tags: patch

Tags: patch


Hello,

tab-first-completion does not work correctly at the moment, and 
indent-for-tab-command must be modified in several ways to take 
its meaning into account correctly :

Since syntax-after returns a list and not an integer, the forms 
like (eql 2 syn) will always return nil. This was introduced by 
commit c7234011518. We partially revert that commit, although it 
would have been possible to solve this issue by wrapping 
(syntax-after (point)) with syntax-class like so :


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diff --git a/lisp/indent.el b/lisp/indent.el
index 89de0a1d7d1..e5f2acdd33b 100644
--- a/lisp/indent.el
+++ b/lisp/indent.el
@@ -171,7 +171,7 @@ prefix argument is ignored."
     (let ((old-tick (buffer-chars-modified-tick))
           (old-point (point))
 	  (old-indent (current-indentation))
-          (syn (syntax-after (point))))
+          (syn (syntax-class (syntax-after (point)))))
 
       ;; Indent the line.
       (or (not (eq (indent--funcall-widened indent-line-function) 'noindent))

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Feel free to change the commit if you prefer this way.

Then, the semantic of word-or-paren and word-or-paren-or-punct is 
not correctly implemented : in the current state, if 
tab-first-completion is set to word-or-paren, and if 
tab-always-indent is set to complete, and we press tab in the 
middle of a word, the word will get autocompleted despite the 
docstring promising the contrary because :

The following form will correctly return nil :

(and (memq tab-first-completion
           '(word word-or-paren word-or-paren-or-punct))
     (not (memq 2 syn)))

But this one will return non-nil :

(and (memq tab-first-completion
           '(word-or-paren word-or-paren-or-punct))
     (not (or (eql 4 syn)
              (eql 5 syn))))

Since syn is equal to (2) (we are within a word).

The constraints need to be cumulative, since they are evaluated 
until one succeeds. So we simply cumulate them so that 
word-or-paren cannot succeed where word could not, and 
word-or-paren-or-punct cannot succeed when word-or-paren could 
not.

This is my first contribution with email. I have tried to follow 
the guidelines specified in CONTRIBUTE and Sending-Patches. Feel 
free to change the commit message or ask me to do it. I have 
already attributed the Copyright to the FSF because of a previous 
contribution.

Best,

Aymeric Agon-Rambosson


In GNU Emacs 29.1 (build 2, x86_64-pc-linux-gnu, X toolkit, cairo
 version 1.16.0, Xaw3d scroll bars) of 2023-09-20, modified by 
 Debian
 built on X570GP
Windowing system distributor 'The X.Org Foundation', version 
11.0.12101007
System Description: Debian GNU/Linux 12 (bookworm)

Configured using:
 'configure --build x86_64-linux-gnu --prefix=/usr
 --sharedstatedir=/var/lib --libexecdir=/usr/libexec
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-libsystemd --with-pop=yes
 --enable-locallisppath=/etc/emacs:/usr/local/share/emacs/29.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/29.1/site-lisp:/usr/share/emacs/site-lisp
 --with-sound=alsa --without-gconf --with-mailutils
 --with-native-compilation=aot --build x86_64-linux-gnu 
 --prefix=/usr
 --sharedstatedir=/var/lib --libexecdir=/usr/libexec
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-libsystemd --with-pop=yes
 --enable-locallisppath=/etc/emacs:/usr/local/share/emacs/29.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/29.1/site-lisp:/usr/share/emacs/site-lisp
 --with-sound=alsa --without-gconf --with-mailutils
 --with-native-compilation=aot --with-x=yes --with-x-toolkit=lucid
 --with-toolkit-scroll-bars --without-gsettings 'CFLAGS=-g -O2
 -ffile-prefix-map=/build/emacs-G3TJOq/emacs-29.1+1=. -fstack-protector-strong
 -Wformat -Werror=format-security -Wall' 'CPPFLAGS=-Wdate-time
 -D_FORTIFY_SOURCE=2' LDFLAGS=-Wl,-z,relro'

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From 8afb0f0ec8e645b41c8da2a5d5156e63fc04bdbd Mon Sep 17 00:00:00 2001
From: Aymeric Agon-Rambosson <aymeric.agon@yandex.com>
Date: Tue, 14 Nov 2023 00:03:46 +0100
Subject: [PATCH] Repair tab-always-indent

Take the values word, word-or-paren, word-or-paren-or-punct correctly
into account in the function indent-for-tab-command :
* syntax-after returns a list, not an integer, either memq or member
must be used (partial revert of c7234011518).
* the constraints on completion-at-point must be cumulative when we go
from word to word-or-paren to word-or-paren-or-punct. Otherwise, tab
always complete with values word-or-paren or word-or-paren-or-punct,
which is not what the docstring seems to say
---
 lisp/indent.el | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/lisp/indent.el b/lisp/indent.el
index 89de0a1d7d1..de8101dc76e 100644
--- a/lisp/indent.el
+++ b/lisp/indent.el
@@ -191,13 +191,17 @@ prefix argument is ignored."
                       (eolp))
                  (and (memq tab-first-completion
                             '(word word-or-paren word-or-paren-or-punct))
-                      (not (eql 2 syn)))
+                      (not (memq 2 syn)))
                  (and (memq tab-first-completion
                             '(word-or-paren word-or-paren-or-punct))
-                      (not (or (eql 4 syn)
-                               (eql 5 syn))))
+                      (not (or (memq 2 syn)
+                               (memq 4 syn)
+                               (memq 5 syn))))
                  (and (eq tab-first-completion 'word-or-paren-or-punct)
-                      (not (eql 1 syn)))))
+                      (not (or (memq 2 syn)
+                               (memq 4 syn)
+                               (memq 5 syn)
+                               (memq 1 syn))))))
         (completion-at-point))
 
        ;; If a prefix argument was given, rigidly indent the following
-- 
2.39.2