Toplevel Loop Problems...

[waander@cs.UMD.EDU (Bill Andersen)]

  I am using this toplevel loop in a standalone application.  Most of
it is borrowed from the "Math Loop" example in ccl;examples.  I just
need to use Fred editor windows with the application so as to be able
to evaluate forms from the editor, by EVALing forms from
GET-NEXT-FORM.

  The problem is that the call to GET-NEXT-FORM does not seem to
remove anything from the *terminal-io* queue.  When I quit my toplevel
loop, all the queued forms get evaluated (presumably by the normal
TOPLEVEL-LOOP function.

  Can someone tell me why this doesn't work, and what to do about it?
Weren't there some difficulties with GET-NEXT-FORM reported earlier?

  Another question: Why does the example code include a
MULTIPLE-VALUE-BIND when MESSAGE-DIALOG apparently only returns one
value?  Thanks in advance.

   ...Bill (waander@cs.umd.edu)

(defun inner-main-loop (&aux abort-or-cancel-p)
  (multiple-value-bind (result error-p)
    (catch-error-quietly
      (setq abort-or-cancel-p
            (catch-abort
              (catch-cancel
                ;; Process forms normally
                (eval (ask *terminal-io* (get-next-form)))
                (event-dispatch))))
      (when (or (eq abort-or-cancel-p :abort)
                (eq abort-or-cancel-p :cancel))
        (message-dialog (format nil "~aed." abort-or-cancel-p))))
    (when error-p
      (unless (y-or-n-dialog
               (format nil "The following error occured:~%~s~%Continue, or quit the application?"
                       (apply #'format nil result))
               :yes-text "Continue"
               :no-text "Quit"
               :cancel-text nil)   ;no cancel button
        (app-quit)))))