bug#10032: 24.0.91; "C-x C-<SPC>" seems broken

bug#10032: 24.0.91; "C-x C-<SPC>" seems broken

[Dani Moncayo]

From "emacs -Q":
1. Move point to the second line and set the mark there (C-<SPC> C-<SPC>).
2. Move point to the third line and set the mark there.
3. Move point to the fourth line.
4. Type "C-x C-<SPC>".

Expected result: Point jumps to the more recent mark, i.e., to the third line.
Observed result: Point jumps to the second line.  Moreover, subsequent
"C-x C-<SPC>" don't cycle through the marks.


In GNU Emacs 24.0.91.1 (i386-mingw-nt6.1.7601)
 of 2011-11-11 on DANI-PC
Windowing system distributor `Microsoft Corp.', version 6.1.7601
configured using `configure --with-gcc (4.5)'

-- 
Dani Moncayo

bug#10032: 24.0.91; "C-x C-<SPC>" seems broken

[Johan Bockgård]

Dani Moncayo <dmoncayo@gmail.com> writes:

> From "emacs -Q":
> 1. Move point to the second line and set the mark there (C-<SPC> C-<SPC>).
> 2. Move point to the third line and set the mark there.
> 3. Move point to the fourth line.
> 4. Type "C-x C-<SPC>".
>
> Expected result: Point jumps to the more recent mark, i.e., to the third line.
> Observed result: Point jumps to the second line.  Moreover, subsequent
> "C-x C-<SPC>" don't cycle through the marks.

This is intentional. According to the doc string of set-mark-command:

    Also push the old mark on global mark ring, if the previous mark was
    set in another buffer.

On the other hand, the manual disagrees:

    Each time you set a mark, in any buffer, this is recorded in the
    global mark ring in addition to the current buffer's own mark ring.

    -- (info "(emacs) Global Mark Ring")

bug#10032: 24.0.91; "C-x C-<SPC>" seems broken

[Dani Moncayo]

> This is intentional. According to the doc string of set-mark-command:
>
>    Also push the old mark on global mark ring, if the previous mark was
>    set in another buffer.

Good point (I didn't notice it).  That explains the current behavior,
although it would be more precise to say "... if the previous mark was
set in another buffer (or there is no previous mark).".

> On the other hand, the manual disagrees:
>
>    Each time you set a mark, in any buffer, this is recorded in the
>    global mark ring in addition to the current buffer's own mark ring.
>
>    -- (info "(emacs) Global Mark Ring")
>

That node of the Emacs manual was the culprit of my confusion, so it
should be fixed.

Thanks.

-- 
Dani Moncayo

bug#10032: 24.0.91; "C-x C-<SPC>" seems broken

[Johan Bockgård]

Dani Moncayo <dmoncayo@gmail.com> writes:

> That node of the Emacs manual was the culprit of my confusion, so it
> should be fixed.

The manual actually used to say

    In addition to the ordinary mark ring that belongs to each buffer,
    Emacs has a single "global mark ring".  It records a sequence of
    buffers in which you have recently set the mark, so you can go back
    to those buffers.

    Setting the mark always makes an entry on the current buffer's mark
    ring.  If you have switched buffers since the previous mark setting,
    the new mark position makes an entry on the global mark ring also.
    The result is that the global mark ring records a sequence of
    buffers that you have been in, and, for each buffer, a place where
    you set the mark.

before it was "fixed".

2008-06-26  Chong Yidong  <cyd@stupidchicken.com>

	* mark.texi (Shift selection): New node.
	(Mark): Copyedits.
	(Persistent Mark): Move to the end of the chapter.

bug#10032: 24.0.91; "C-x C-<SPC>" seems broken

[Chong Yidong]

Johan Bockgård <bojohan@gnu.org> writes:

> The manual actually used to say
>
>     In addition to the ordinary mark ring that belongs to each buffer,
>     Emacs has a single "global mark ring".  It records a sequence of
>     buffers in which you have recently set the mark, so you can go back
>     to those buffers.
>
>     Setting the mark always makes an entry on the current buffer's mark
>     ring.  If you have switched buffers since the previous mark setting,
>     the new mark position makes an entry on the global mark ring also.
>     The result is that the global mark ring records a sequence of
>     buffers that you have been in, and, for each buffer, a place where
>     you set the mark.
>
> before it was "fixed".
>
> 2008-06-26  Chong Yidong  <cyd@stupidchicken.com>
>
> 	* mark.texi (Shift selection): New node.
> 	(Mark): Copyedits.
> 	(Persistent Mark): Move to the end of the chapter.

Sorry for the confusion; I've checked in a fix.