Re: buffer-list and desktop

[Kevin Rodgers]

David Kastrup wrote:
> Jesper Harder <harder@myrealbox.com> writes:
>>Or if you don't mind requiring cl:

I do mind.  :-)

>>(delete-if-not
>>   (lambda (buf)
>>     (desktop-save-buffer-p (buffer-file-name buf) (buffer-name buf)
>>                            (buffer-local-value 'major-mode buf)))
>>   (buffer-list))

buffer-local-value is not defined in Emacs 21.3.  Too bad, because
passing the buffer as an argument should be faster than using
with-current-buffer.

> Still slow because of one bind/unbind per iteration.  If you want to
> do it that way, anyway, you could avoid cl by using
>
> (delq nil
>   (mapcar
>     (lambda (buf)
>       (and (desktop-save-buffer-p ...)
>            buf))
>     (buffer-list)))
>
> with hardly more effort.

Your first idea to just push each buffer that satisifies the predicate
on to a result list is better.  And I don't share your aversion to
variable bindings.  :-)

So here's what I've come up with.  The real problem I see is that the
buffer browsing commands (list-buffers and electric-buffer-list) don't
take the list of buffers as an argument, so you can't write new
desktop-save- versions of those commands that use the result of this
function.

(defun desktop-save-buffer-list ()
  "Return the list of buffers that `desktop-save' would save."
  (let ((buffer-list '()))
    (mapc (lambda (buffer)
            (with-current-buffer buffer
              (when (desktop-save-buffer-p (buffer-file-name)
                                           (buffer-name)
                                           major-mode)
                (setq buffer-list (cons buffer buffer-list)))))
          (buffer-list))
    (nreverse buffer-list)))

--
Kevin Rodgers