[plt-scheme] Graphics Questions

From: Doug Williams (m.douglas.williams at gmail.com)
Date: Sun Nov 25 20:41:35 EST 2007

Thanks, that works great.  Now I just have to figure out why.  Seems I have
some reading to do.  :)

Doug

On Nov 25, 2007 6:01 PM, Matthew Flatt <mflatt at cs.utah.edu> wrote:

> At Sun, 25 Nov 2007 17:52:54 -0700, "Doug Williams" wrote:
> > I get an error "continuation application: attempt to cross a
> continuation
> > barrier".  I assume MrEd is using threads or other elements that cause
> the
> > continuation barrier.
>
> Yes.
>
> > Does anyone have a suggestions?
>
> Delimited continuations. Wrap the body of your callback in
> `call-with-continuation-prompt':
>
>   (call-with-continuation-prompt
>     (lambda ()
>       (if *break*
>           (begin
>             (set! *break* #f)
>             (*continue*))
>           (test-run))))
>
>
> Matthew
>
>
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