Clear Emacs Buffer programmatically from Common Lisp

[Frank Zalkow]

Hey Lispers,

I would like to know if it is possible to clear the current REPL in Emacs from CL.

If I do it from emacs lisp
M-x eval-expression: (let ((inhibit-read-only t)) (interactive) (erase-buffer))
it works fine.

So I thought it should work to do
M-x eval-expression: (setq slime-enable-evaluate-in-emacs t)

and call a function like this

(defun clear-emacs-buffer ()
(swank:eval-in-emacs
'(let ((inhibit-read-only t)) (interactive) (erase-buffer))))

But calling this function just returns NIL and doesn't clear the buffer.

Is this a wrong approach?

Thanks alot for any hints!

Best

Frank

[smh]

Possibly with swank the eval-in-emacs doesn't happen in the repl buffer, so you are clearing some other buffer. Don't know the details of swank, but in the ACL Emacs-Lisp interface the following works and may suggest something to try with swank.

(lep::eval-in-emacs
"(save-excursion (set-buffer \"*common-lisp*\") (erase-buffer))")

[Pascal J. Bourguignon]

Frank Zalkow <fza...@gmail.com> writes:

> Hey Lispers,
>
> I would like to know if it is possible to clear the current REPL in Emacs from CL.
>
> If I do it from emacs lisp
> M-x eval-expression: (let ((inhibit-read-only t)) (interactive) (erase-buffer))
> it works fine.
>
> So I thought it should work to do
> M-x eval-expression: (setq slime-enable-evaluate-in-emacs t)
>
> and call a function like this
>
> (defun clear-emacs-buffer ()
> (swank:eval-in-emacs
> '(let ((inhibit-read-only t)) (interactive) (erase-buffer))))
>
> But calling this function just returns NIL and doesn't clear the buffer.

M-x slime RET C-h k C-c M-o

indicates the command to use is slime-repl-clear-buffer, not
erase-buffer.

(swank:eval-in-emacs 'slime-repl-clear-buffer)

fails with an obvious re-entrancy error.

Therefore:

(swank:eval-in-emacs '(progn
(run-at-time 1 nil 'slime-repl-clear-buffer)
nil))

should do it.


--
__Pascal Bourguignon__ http://www.informatimago.com/
“The factory of the future will have only two employees, a man and a
dog. The man will be there to feed the dog. The dog will be there to
keep the man from touching the equipment.” -- Carl Bass CEO Autodesk

[Frank Zalkow]

Smh, awesome, thanks alot! It works!

Now I have something like this:

(defun clear-emacs-buffer (buffer-name)

(swank:eval-in-emacs
`(let ((inhibit-read-only t))
(interactive)

(save-excursion (set-buffer ,buffer-name)
(erase-buffer)))))

And I can call it like
(clear-emacs-buffer "*slime-repl sbcl*")



Pascal, also thanks to you! That works and is even better because I have not to type the buffer name.

(defun clear-emacs-buffer ()
(swank:eval-in-emacs

'(progn
(run-at-time 0.2 nil 'slime-repl-clear-buffer)
nil)))

I can even do (run-at-time 0.0 ...) - it just causes the last expression to remain on the screen.

Thanks both of you and best,

Frank