Re: Condition Question

[kab (Kim Barrett)]

> I am developing a progress reporting module that
> enables one have a window showing progress while doing
> some computations. The progress window behaves exactly like
> the system 7 finder's file copy window. It doesn't keep
> you from switching application, etc...
> 
> Everything work fine except if an error occurs.
> If an error occurs, I would need to be able to do the following:
> 
> Before going to the debugger,
>   - reenable MCL's menus
>   - hide the progress window
> 
> If the error is continued from
>   - redisable MCL's menus
>   - show the progress window

This looks like a job for *debugger-hook* and invoke-debugger.  Making up some 
names as I go along, perhaps something like the following will do what you 
want.

... in the expansion for with-progress-reporting-context (I made up this name)

  (let* ((old-hook *debugger-hook*)
         (new-hook #'(lambda (c h)
                       (declare (ignore h))
                       (let ((*debugger-hook* old-hook))
                         (without-progress-reporting-context ;made up name
                           (invoke-debugger c)))))
         (*debugger-hook* new-hook))
    (declare (dynamic-extent new-hook))
    ...