Re: Saving the selection before killing

[David Kastrup]

Richard Stallman <address@hidden> writes:

>     The main problem I saw with it was working over non-local X
>     connections where it could lead to annoying and inexplicable
>     slowdowns.
>
> Is that an observation or a theoretical conclusion?

That's what people frequently were complaining about on the XEmacs
lists, and I am not really sure we did not also have a time with
similar complaints.  Now that was, unless I am mistaken, for large
selections _from_ Emacs that were picked up elsewhere (like
mark-whole-buffer would do), whereas the case we are debating is Emacs
picking up selections from outside, and maybe megabyte selections are
less common outside than inside.

But if one is running more than one Emacs instance (and I don't know
under which circumstances Emacs might offer _itself_ a selection),
then we _have_ the same porential for large selections flying around.

> The question is how much slowdown this feature adds when there is no
> selection.

Uh, why?  Can we rule out that there are large selections?

> How long does it take to determine that there is no selection?

That should be reasonably fast.  I would expect noticeable effects at
most when running keyboard macros.  However, keyboard macros that yank
stuff are not really infrequent, and when one is running them on a
whole buffer, checking the display remotely every time _might_
conceivably make a difference.  In contrast to the above observation,
this is, for now, a theoretical conclusion.

This theoretical conclusion also means that if you go elsewhere while
your keyboard macro runs and mark some text with the mouse, the
keyboard macro will suddenly do something different.

Perhaps we should ignore selections altogether when executing keyboard
macros, not just in this case.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum