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bug#4608: Description of `buffer-swap-text' is vague and inadequate.
From: |
Stefan Monnier |
Subject: |
bug#4608: Description of `buffer-swap-text' is vague and inadequate. |
Date: |
Thu, 01 Oct 2009 09:56:00 -0400 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/23.1.50 (gnu/linux) |
> 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