bug#16799: 24.3.50; delete-selection-mode and electric-pair-mode interaction

bug#16799: 24.3.50; delete-selection-mode and electric-pair-mode interaction

[Harald Hanche-Olsen]

Starting from emacs -Q, switch to the *scratch* buffer and run:

M-x electric-pair-mode RET
M-x delete-selection-mode RET

Place the cursor in the first line, but not at the befinning,
and type C-space C-a.

Now the region is active, and point is at the beginning of the buffer.
Type any character bound to self-insert-command.

Result:

Error in pre-command-hook (delete-selection-pre-hook): (args-out-of-range 0 1)

As a side effect, delete-selection-pre-hook is removed from
pre-command-hook, effectively disabling delete-selection-mode.

In GNU Emacs 24.3.50.1 (x86_64-apple-darwin13.0.0,
  NS apple-appkit-1265.00) of 2014-02-18 on airy
Windowing system distributor `Apple', version 10.3.1265
Configured using:
 `configure --with-ns'

The source code was pulled from the git repo less than an hour ago.

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

– Harald

bug#16799: 24.3.50; delete-selection-mode and electric-pair-mode interaction

[Juanma Barranquero]

On Tue, Feb 18, 2014 at 9:47 PM, Harald Hanche-Olsen
<hanche@math.ntnu.no> wrote:

> Error in pre-command-hook (delete-selection-pre-hook): (args-out-of-range 0 1)

I think something like this is needed to avoid
electric-pair-syntax-info parsing before the start of the
region/buffer.

=== modified file 'lisp/elec-pair.el'
--- lisp/elec-pair.el   2014-02-03 00:28:57 +0000
+++ lisp/elec-pair.el   2014-02-19 22:18:02 +0000
@@ -215,8 +215,10 @@
 `electric-pair-pairs' or `electric-pair-text-pairs' were used to
 lookup syntax.  STRING-OR-COMMENT-START indicates that point is
 inside a comment of string."
-  (let* ((pre-string-or-comment (nth 8 (save-excursion
-                                         (syntax-ppss (1- (point))))))
+  (let* ((pre-string-or-comment (if (> (point) (point-min))
+                                   (nth 8 (save-excursion
+                                            (syntax-ppss (1- (point)))))
+                                 t))
          (post-string-or-comment (nth 8 (syntax-ppss (point))))
          (string-or-comment (and post-string-or-comment
                                  pre-string-or-comment))

bug#16799: 24.3.50; delete-selection-mode and electric-pair-mode interaction

[Stefan Monnier]

> -  (let* ((pre-string-or-comment (nth 8 (save-excursion
> -                                         (syntax-ppss (1- (point))))))
> +  (let* ((pre-string-or-comment (if (> (point) (point-min))
> +                                   (nth 8 (save-excursion
> +                                            (syntax-ppss (1- (point)))))
> +                                 t))

Looks right, except that I'd write (not (bobp)) instead of (> (point)
(point-min)).


        Stefan

bug#16799: 24.3.50; delete-selection-mode and electric-pair-mode interaction

[Juanma Barranquero]

On Thu, Feb 20, 2014 at 5:49 AM, Stefan Monnier
<monnier@iro.umontreal.ca> wrote:

> Looks right, except that I'd write (not (bobp)) instead of (> (point)
> (point-min)).

Yes, thanks. I always forget bobp.

I've installed the patch using

   (or (bobp)
        (nth ...))

which is shorter and pretty clear IMO.