Re: bug#1406: backward-up-list reports scan error incorrectly?

[xah lee <xah@xahlee.org>]

On Nov 27, 4:19 am, Alan Mackenzie <a...@muc.de> wrote:
 > Hi, Xah!
 >
 > > > though, isn't this something easy to fix?
 > > No, because it isn't a bug.  It's the way the function is meant  
to work.
 > > If there is a bug, it's that the doc-string (and maybe the elisp  
manual,
 > > I haven't looked) is vague and incomplete.
 >
 > I've amended the Emacs manual (.../doc/emacs/programs.texi) and  
the doc
 > strings of `backward-up-list' and several similar functions
 > (.../lisp/emacs-lisp/lisp.el).
 >
 > If you're interested, have a look at the changes in
 > <http://cvs.savannah.gnu.org/viewvc/emacs/?root=emacs>.

Thanks Alan.

I'd rather hope for a fix instead of change wording to reflect  
current situation.

You argued in bug list that the issue is not simple essentially due  
to the fact that straight quote chars are not matching pairs.

That is true, but i think given today's tech and computing power, we  
can over come this. Just assume that double quotes in the source code  
are matched, since they are most of the time. In the few cases when  
the backward-up-list went to the wrong place due to un-matched double  
quote, i think that's ok. (as opposed to, it stops dead and utter a  
beep.)

alternatively, if the cursor is inside double quote, then issue a  
warning in the messag area that the result may not be correct.

Also, since this works in text-mode, so apparently this can work. A  
implementation is to temporarily switch to that mode, do the cursor  
move, then switch back. Or temp set the syntax table to whatever chat  
that made text-mode work and emacs-lisp-mode not work.

In general, my feeling is that moving around nested pairs is not a  
some insurmountable issue, that given today's technology and  
software, it seems wimpy to tell users that backward-up-list won't  
work if it's inside double quotes. Much complex problems are solved  
today in emacs, in other IDEs, etc.

Just my opinions. Thanks.

   Xah
∑ http://xahlee.org/

☄



On Nov 27, 2008, at 4:19 AM, Alan Mackenzie wrote:

Hi, Xah!

>> though, isn't this something easy to fix?

> No, because it isn't a bug.  It's the way the function is meant to  
> work.
> If there is a bug, it's that the doc-string (and maybe the elisp  
> manual,
> I haven't looked) is vague and incomplete.

I've amended the Emacs manual (.../doc/emacs/programs.texi) and the doc
strings of `backward-up-list' and several similar functions
(.../lisp/emacs-lisp/lisp.el).

If you're interested, have a look at the changes in
<http://cvs.savannah.gnu.org/viewvc/emacs/?root=emacs>.

-- 
Alan Mackenzie (Nuremberg, Germany).

☄