bug#37133: 27.0.50; use Autoconf mode instead of m4 for acinclude.m4, aclocal.m4 and acsite.m4

bug#37133: 27.0.50; use Autoconf mode instead of m4 for acinclude.m4, aclocal.m4 and acsite.m4

[Vincent Lefevre]

By default, the m4 mode is used for the acinclude.m4, aclocal.m4 and
acsite.m4 files. It would be better to use the more specific Autoconf
mode for these files (like configure.ac).


In GNU Emacs 27.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.10)
 of 2019-08-20 built on cventin
Repository revision: 50dc4ca8d02a466a7236765edf83ae7cfb02d74c
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12004000
System Description: Debian GNU/Linux bullseye/sid

Recent messages:
Loading /home/vlefevre/share/emacs/site-lisp/mutteditor.el (source)...done
Loading time...done
For information about GNU Emacs and the GNU system, type C-h C-a.

Configured using:
 'configure --prefix=/usr/local/emacs-trunk'

Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND GPM DBUS GSETTINGS GLIB NOTIFY INOTIFY
ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM THREADS LIBSYSTEMD PDUMPER LCMS2
GMP

Important settings:
  value of $LC_COLLATE: POSIX
  value of $LC_CTYPE: en_US.UTF-8
  value of $LC_TIME: en_DK
  value of $LANG: POSIX
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  display-time-mode: t
  show-paren-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr warnings emacsbug message rmc puny dired
dired-loaddefs format-spec rfc822 mml easymenu mml-sec password-cache
epa derived epg epg-config gnus-util rmail rmail-loaddefs
text-property-search time-date subr-x seq byte-opt gv bytecomp
byte-compile cconv mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils time cus-start cus-load paren cc-styles
cc-align cc-engine cc-vars cc-defs edmacro kmacro cl-loaddefs cl-lib
tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type
mwheel term/x-win x-win term/common-win x-dnd tool-bar dnd fontset image
regexp-opt fringe tabulated-list replace newcomment text-mode elisp-mode
lisp-mode prog-mode register page menu-bar rfn-eshadow isearch timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame cl-generic cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932
hebrew greek romanian slovak czech european ethiopic indian cyrillic
chinese composite charscript charprop case-table epa-hook jka-cmpr-hook
help simple abbrev obarray minibuffer cl-preloaded nadvice loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote threads dbusbind inotify lcms2 dynamic-setting
system-font-setting font-render-setting move-toolbar gtk x-toolkit x
multi-tty make-network-process emacs)

Memory information:
((conses 16 65441 9020)
 (symbols 48 8743 1)
 (strings 32 20758 2709)
 (string-bytes 1 700989)
 (vectors 16 11319)
 (vector-slots 8 144202 10690)
 (floats 8 24 22)
 (intervals 56 217 0)
 (buffers 992 12))

bug#37133: 27.0.50; use Autoconf mode instead of m4 for acinclude.m4, aclocal.m4 and acsite.m4

[Lars Ingebrigtsen]

Vincent Lefevre <vincent@vinc17.net> writes:

> By default, the m4 mode is used for the acinclude.m4, aclocal.m4 and
> acsite.m4 files. It would be better to use the more specific Autoconf
> mode for these files (like configure.ac).

I don't know these modes well, but the doc string for `autoconf-mode'
says:

---
Major mode for editing Autoconf configure.ac files.
---

So would using it for these other .m4 files be appropriate?  If it is,
the following patch would fix the problem.

diff --git a/lisp/files.el b/lisp/files.el
index f76635017d..2a84c2c48f 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -2719,6 +2719,8 @@ auto-mode-alist
      ("\\.bib\\'" . bibtex-mode)
      ("\\.bst\\'" . bibtex-style-mode)
      ("\\.sql\\'" . sql-mode)
+     ;; These .m4 files are Autoconf files.
+     ("\\(acinclude\\|aclocal\\|acsite\\)\\.m4\\'" . autoconf-mode)
      ("\\.m[4c]\\'" . m4-mode)
      ("\\.mf\\'" . metafont-mode)
      ("\\.mp\\'" . metapost-mode)


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

bug#37133: 27.0.50; use Autoconf mode instead of m4 for acinclude.m4, aclocal.m4 and acsite.m4

[Glenn Morris]

Lars Ingebrigtsen wrote:

> So would using it for these other .m4 files be appropriate?

Note that eg aclocal.m4 uses it automatically via a file-local variable.
See eg
http://git.savannah.gnu.org/cgit/automake.git/tree/bin/aclocal.in#n971

So automake's authors thought it was the right thing to do.

bug#37133: 27.0.50; use Autoconf mode instead of m4 for acinclude.m4, aclocal.m4 and acsite.m4

[Lars Ingebrigtsen]

Glenn Morris <rgm@gnu.org> writes:

> Lars Ingebrigtsen wrote:
>
>> So would using it for these other .m4 files be appropriate?
>
> Note that eg aclocal.m4 uses it automatically via a file-local variable.
> See eg
> http://git.savannah.gnu.org/cgit/automake.git/tree/bin/aclocal.in#n971
>
> So automake's authors thought it was the right thing to do.

OK; I've now applied the patch.

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