Re: comint read-only prompt

[Miles Bader <miles@gnu.org>]

On Tue, Aug 20, 2002 at 03:01:32PM -0700, JD Smith wrote:
> Sorry, poor choice of words.  I did notice that snapshot-last-prompt, in
> the CVS version, now adds text properties as opposed to "freeing" the
> overlay, and that it gets called not just when a new prompt is created,
> but *many* times, e.g. every time a command is sent (which occurs in the
> background all the time in IDLWAVE).

I'm confused by what you mean -- that's when snapshot-last-prompt has
_always_ been called, when input is sent (and it's not called at all when `a
new prompt is created').  It should be called exactly the same number of
times now as it was before.

> So, in the present scheme, the current prompt has either
> overlay-properties, or redundant overlay+text-properties.  All old prompts
> have just text-properties.  In this context, I can't see how overlays are
> uniquely needed, since they aren't predictably present by themselves...

That simply isn't true; the _majority_ of the time, in a normal shell
session, the overlay alone is responsible for the last prompt (there may be a
brief instant after you've send a command, and before the process has sent
any output, when they may overlap, but that's harmless).  As the process
sends output after a command, the overlay is moved so that it covers anything
that `looks like a prompt', which may happen many times.  [and
snapshot-last-prompt is never called _at all_]

-Miles
-- 
P.S.  All information contained in the above letter is false,
      for reasons of military security.