Re: [Emacs-diffs] /srv/bzr/emacs/trunk r103444: * lisp/facemenu.el (list-colors-display): Use with-help-window (Bug#8048).

[martin rudalics]

> > Unfortunately, we can't fill the buffer _before_ calling
> > `with-help-window' because, as the comment above indicates,
> > `list-colors-print' wants to know the width of the window _before_
> > filling the buffer.

> That's a common need, so with-help-window should display the buffer
> before running the code.

Suppose we rewrote `with-output-to-temp-buffer' in Elisp then we would
probably come up with something like the following code:

     (let ((standard-output buffer))
       (setq value (progn ,@body)))

     (with-current-buffer buffer
       (set-buffer-modified-p nil)
       (goto-char (point-min)))

     (if (functionp temp-buffer-show-function)
         (funcall temp-buffer-show-function buffer)
       (let ((window (display-buffer buffer)))
         (when window
           ;; Temporarily select window (and implicitly make the buffer
           ;; current).
           (with-selected-window window
             (setq minibuffer-scroll-window window)
             (set-window-start window (point-min))
             (set-window-point window (point))
             (run-hooks 'temp-buffer-show-hook)))))

     ;; Return last value of BODY.
     value))

If we now wanted to display the buffer _before_ evaluating BODY, we'd
have to splice in the evaluation into `temp-buffer-show-function'.  I
don't have the slightest idea how this could be reasonably done :-(

martin