🚀 go-pugleaf

I just added this text to the Lisp manual:

  Many filter functions sometimes or always insert the text in the
process's buffer, mimicking the actions of Emacs when there is no
filter.  Such filter functions need to use @code{set-buffer} in order to
be sure to insert in that buffer.  To avoid setting the current buffer
semipermanently, these filter functions must use @code{unwind-protect}
to make sure to restore the previous current buffer.  They should also
update the process marker, and in some cases update the value of point.
Here is how to do these things:

@example
(let ((moving (= (point) (process-mark proc)))
      (old-buffer (current-buffer)))
  (set-buffer (process-buffer proc))
  (unwind-protect
      (save-excursion
	;; Insert the text, moving the process-marker.
	(goto-char (process-mark proc))
	(insert string)
	(set-marker (process-mark proc) (point)))
    (set-buffer old-buffer))
  (if moving (goto-char (process-mark proc))))
@end example