bug#4617: Description of `buffer-swap-text' is vague and inadequate.

[Alan Mackenzie]

Hi, Stefan,

On Thu, Oct 01, 2009 at 09:56:00AM -0400, Stefan Monnier wrote:
> > 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.

Ah.  OK, got you!  I'll patch in a "the" sometime, to make it "swaps THE
text between .....".  But overlays?  Overlays aren't part of the text
(thought text-properties are).  But this has probably been talked through
anyway, some long time ago.

Sounds like a brilliant idea, though - you could use this for several
major modes in the same "buffer", somehow.  

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

> grep disagrees:

Apologies.  I was grepping for "buffer-swap-text".

> -- Stefan

-- 
Alan Mackenzie (Nuremberg, Germany).