GNU bug report logs - #4608
Description of `buffer-swap-text' is vague and inadequate.

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Message #5 received at submit <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Alan Mackenzie <acm <at> muc.de>
Cc: bug-gnu-emacs <at> gnu.org
Subject: Re: Description of `buffer-swap-text' is vague and inadequate.
Date: Thu, 01 Oct 2009 09:56:00 -0400

> The Elisp manual page "Swapping Text", says that `buffer-swap-text'
> "swaps text between the current buffer and its argument BUFFER."

> This tells me nothing.  I'd have to read the source (or maybe try it
> out) to find out what this function does.

> What does "swap" mean here?  How much text is "swapped".  What does
> "between" mean?

> A naive guess would suggest this command takes a bit of text out of
> buffer A and dumps it into buffer B, simultaneously moving a bit of B
> into A.

No, it swaps the whole freakin' text, including text-properties,
markers, and overlays.  So at the end, buffer A has buffer B's text and
vice versa.

> There is also no entry in .../src/ChangeLog (or ChangeLog.10, ...)
> marking the introduction of this command.

grep disagrees:

   % grep buffer.swap.text src/ChangeLog*
   src/ChangeLog:  * buffer.c (Fbuffer_swap_text): Use POINTER_TYPE.
   src/ChangeLog:  * buffer.c (Fbuffer_swap_text) [REL_ALLOC]: Reset ralloc's internal
   src/ChangeLog:  * buffer.c (Fbuffer_swap_text): Signal error if swapping a dead buffer.
   src/ChangeLog:  * buffer.c (Fbuffer_swap_text): Remove redundant marker manipulation.
   src/ChangeLog:  * buffer.c (Fbuffer_swap_text): Reset window->point markers.
   src/ChangeLog:  * buffer.c (Fbuffer_swap_text): New function.
   % 


-- Stefan

Message #10 received at 4608 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Juanma Barranquero <lekktu <at> gmail.com>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: Alan Mackenzie <acm <at> muc.de>, 4608 <at> debbugs.gnu.org
Subject: Re: bug#4608: Description of `buffer-swap-text' is vague and 
	inadequate.
Date: Thu, 1 Oct 2009 16:46:27 +0200

On Thu, Oct 1, 2009 at 15:56, Stefan Monnier <monnier <at> iro.umontreal.ca> wrote:

[Stefan, you've duplicated the bug because of Cc: bug-gnu-emacs <at> gnu.org]

> grep disagrees:
>
>   % grep buffer.swap.text src/ChangeLog*
>   src/ChangeLog:  * buffer.c (Fbuffer_swap_text): Use POINTER_TYPE.
>   src/ChangeLog:  * buffer.c (Fbuffer_swap_text) [REL_ALLOC]: Reset ralloc's internal
>   src/ChangeLog:  * buffer.c (Fbuffer_swap_text): Signal error if swapping a dead buffer.
>   src/ChangeLog:  * buffer.c (Fbuffer_swap_text): Remove redundant marker manipulation.
>   src/ChangeLog:  * buffer.c (Fbuffer_swap_text): Reset window->point markers.
>   src/ChangeLog:  * buffer.c (Fbuffer_swap_text): New function.
>   %

Or, using our own tool:

C:\emacs\src> grep-changelog --text=buffer.swap.text --reverse

2008-02-25  Stefan Monnier  <monnier <at> iro.umontreal.ca>

        * buffer.c (Fbuffer_swap_text): New function.
        (syms_of_buffer): Defsubr it.

2008-09-07  Stefan Monnier  <monnier <at> iro.umontreal.ca>

        * buffer.c (Fbuffer_swap_text): Reset window->point markers.

2008-11-21  Stefan Monnier  <monnier <at> iro.umontreal.ca>

        * buffer.c (Fbuffer_swap_text): Remove redundant marker manipulation.
        Fix copy/paste typo.  Add checks.

2008-12-09  Chong Yidong  <cyd <at> stupidchicken.com>

        * buffer.c (Fbuffer_swap_text): Signal error if swapping a dead buffer.

2008-12-24  Jason Rumney  <jasonr <at> gnu.org>

        * buffer.c (Fbuffer_swap_text) [REL_ALLOC]: Reset ralloc's internal
        record of what points where.  (Bug#716)

2008-12-25  Jason Rumney  <jasonr <at> gnu.org>

        * buffer.c (Fbuffer_swap_text): Use POINTER_TYPE.


    Juanma

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