Re: unexpected behaviour of `with-output-to-string'
Alexander Reinwarth <alexander(a)reinwarth.de> wrote:
The problem seems to be in `with-output-to-string', which opens
temporary buffers, but instead of removing them, just deletes the
buffers' content.
I locally defined a substitute for `with-output-to-string', replacing
the last line of
,----
| (defmacro with-output-to-string (&rest forms)
| "Collect output to `standard-output' while evaluating FORMS and return
| it as a string."
| ;; by "William G. Dubuque" <wgd(a)zurich.ai.mit.edu> w/ mods from Stig
| `(with-current-buffer (get-buffer-create
| (generate-new-buffer-name " *string-output*"))
| (setq buffer-read-only nil)
| (buffer-disable-undo (current-buffer))
| (erase-buffer)
| (let ((standard-output (current-buffer)))
| ,＠forms)
| (prog1
| (buffer-string)
| (erase-buffer))))
`----
with
(kill-buffer(current-buffer)))))
and now everything works as expected for me.
Is this something which should be changed in the XEmacs-distribution
or did I just misunderstand the purpose and/or implementation of
`with-output-to-string'?
It should be changed. Here is the GNU version:
(defmacro with-output-to-string (&rest body)
"Execute BODY, return the text it sent to `standard-output', as a
string."
`(let ((standard-output
(get-buffer-create (generate-new-buffer-name " *string-output*"))))
(let ((standard-output standard-output))
,＠body)
(with-current-buffer standard-output
(prog1
(buffer-string)
(kill-buffer nil)))))
I'm not sure why the XEmacs version dorks about doing:
(setq buffer-read-only nil)
(buffer-disable-undo (current-buffer))
(erase-buffer)
with a brand-spanking-new buffer.
Also, the GNU version will only return what was printed to
`standard-output'; BODY can still modify the current buffer, which
seems neat.
--
John Paul Wallington