bug#46420: 28.0.50; Wrong line continuation in double-quoted Octave strings

[Basil L. Contovounesios]

Tags: patch

0. emacs -Q
1. C-x b foo RET
2. M-x octave-mode RET
3. s = "foo C-M-j

This inserts the line continuation marker '...' instead of '\'.

Since Octave 3.8, released over 7 years ago, breaking double-quoted
strings with an ellipsis, or breaking anything else with a backslash, is
deprecated; see https://www.gnu.org/s/octave/NEWS-3.8.html and
(info "(octave) Continuation Lines").

In the Octave 6.1 REPL:

  octave:1> s = "foo...
  warning: '...' continuations in double-quoted character strings are
  obsolete and will not be allowed in a future version of Octave; please
  use '\' instead
  > "
  s = foo
  octave:2> x = [1 \
  warning: using continuation marker \ outside of double quoted strings
  is deprecated and will be removed from a future version of Octave, use
  ... instead
  > ]
  x = 1

I attach a patch which reintroduces the backslash as
octave-string-continuation-marker, alongside the existing ellipsis
octave-continuation-string.

[ I think octave-string-continuation is the perfect name for the
  backslash, but I can imagine it not being very popular ;).
  Naming suggestions welcome. ]

WDYT?

-- 
Basil

In GNU Emacs 28.0.50 (build 1, x86_64-pc-linux-gnu, X toolkit, cairo version 
1.16.0, Xaw3d scroll bars)
 of 2021-02-09 built on tia
Repository revision: bff9bd0d3acff0fa0a50e21bdeca024e71fa518b
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12010000
System Description: Debian GNU/Linux bullseye/sid

Configured using:
 'configure 'CC=ccache gcc' 'CFLAGS=-O2 -march=native' --config-cache
 --prefix=/home/blc/.local --enable-checking=structs
 --with-x-toolkit=lucid --with-file-notification=yes --with-x'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
JSON LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 M17N_FLT MODULES NOTIFY
INOTIFY PDUMPER PNG RSVG SOUND THREADS TIFF TOOLKIT_SCROLL_BARS X11
XAW3D XDBE XIM XPM LUCID ZLIB

0001-Fix-Octave-double-quoted-string-line-continuations.patch
Description: Text Data