how to 'block' the prompt

[Martin Maechler]

>>>>> "DavidB" == David Brahm <brahm at alum.mit.edu>
>>>>>     on Thu, 19 Aug 2004 19:02:02 -0400 writes:

    DavidB> Sebastian Luque <sluque at mun.ca> wrote:
    >> what exactly is the character between the double quotes in that line 5?

    DavidB> It is a Control-A (^A), which you can insert in a
    DavidB> file using ^Q^A in Emacs.  My apologies for sending
    DavidB> mail with a control character embedded in it,
    DavidB> though.  This ought to work equally well, and uses
    DavidB> only printable ascii:

(yes and I believe that's also what I had in that post you mentioned)

    DavidB> (eval-after-load "comint" '(progn
    DavidB>   (setq comint-scroll-to-bottom-on-output 'others)
    DavidB>   (define-key comint-mode-map [up] 'comint-previous-matching-input-from-input)
    DavidB>   (define-key comint-mode-map [down] 'comint-next-matching-input-from-input)
    DavidB>   (define-key comint-mode-map "\C-a" 'comint-bol-or-process-mark) )
    DavidB> )

    DavidB> Again, all glory goes to Martin Maechler

 (blush ... just standing on the shoulders of giants!)

    DavidB> As an added note, I think Martin also has this line
    DavidB> inside his structure: 
    DavidB>    (setq comint-scroll-show-maximum-output t)
    DavidB> which forces the prompt always to the bottom of the S window,

that's correct.
In the mean time we (our group here, in a common emacs
initialization file) additionally have

    (setq comint-scroll-to-bottom-on-output 'others) ; not current

    DavidB>  but I don't like it because I find it too jumpy.

Finally, as you said in your first post, this helps not to
accidentally erase the prompt, but that's still possible and the
origin of this thread was asking how to make the prompt
"read-only" in the *R* (or *S*) buffer. 

In the mean time, I seem to rememeber vaguely that we had tried
this at one point, and had abandoned it for some
reasons. However that was probably before emacs 21. 

Martin