[plt-scheme] solving the halting problem

You probably want <menukey>-k, under the Scheme menu.

Robby

On Jan 3, 2008 10:21 AM, Jos Koot <jos.koot at telefonica.net> wrote:
> I glanced through the article and appreciate your care about safely killing
> threads. In relation to this topic, I have a trivial question. Usually I run
> MzScheme programs  from DrScheme's nice programming environment. As you
> surely will forgive me, not all my programs are correct. They may produce
> wrong results, or worse, they may unintentionally loop forever. If a program
> takes more time than I expect or allow,  I use the break button, which
> happens to react fast nowadays. It is clear to me that the break button does
> not kill threads that may have been spawn by my program. In that case I must
> double click the break button for a complete kill of all processes. But
> sometimes I forget to double click or the break rfesponds so quickly that
> the second click is not honoured. Then there is no other way to stop all
> threads than by quitting DrScheme altogether, or is there? Would it be
> possible and desirable to add a kill button or to convert the break button
> into a kill button after a break? I now that after a complete kill, the
> interactions window no longer works. That is allright of course. Dead is
> dead.
> Jos Koot
>
>
> ----- Original Message -----
> From: "Robby Findler" <robby at cs.uchicago.edu>
> To: <dave at pawfal.org>
> Cc: <plt-scheme at list.cs.brown.edu>
> Sent: Wednesday, January 02, 2008 6:58 PM
> Subject: Re: [plt-scheme] solving the halting problem
>
>
> > Depends what you want to do. Others would say that breaking a thread
> > is a good idea most of the time, but I'd say that killing is the
> > easier route in general, and I'd try that first. To give you an idea
> > of how to use killing and how we think about it, check out this paper:
> >
> >  http://www.cs.utah.edu/plt/kill-safe/
> >
> > Feel free to post if you have questions about it.
> >
> > Robby
> >
> > On Jan 2, 2008 11:34 AM, Dave Griffiths <dave at pawfal.org> wrote:
> >> Ok, thanks - it looks like it's better solved in the Scheme world then.
> >>
> >> Am I right in thinking it's cleaner to shut down a custodian than
> >> breaking
> >> a thread?
> >>
> >>
> >> > The break button calls break-thread on the user's main thread (if the
> >> > usre has created more threads, they won't be broken). The kill button
> >> > shuts down the user's custodian, so you can simulate both of these
> >> > programmatically. (I'm not sure about the embedding answer, but I do
> >> > believe that when you're at the C level that the concurrency is
> >> > cooperative, so you only get breaks at points where you explicitly
> >> > yield control.)
> >> >
> >> > Robby
> >> >
> >> > On Jan 2, 2008 9:04 AM, Dave Griffiths <dave at pawfal.org> wrote:
> >> >> Hi all,
> >> >>
> >> >> I'm interested in how the "break" key in drscheme is implemented -
> >> >> does
> >> >> it
> >> >> kill the (PLT?) thread which the process is currently running in? Is
> >> >> this
> >> >> the best/only way of manually stopping computation?
> >> >>
> >> >> In the context of mzscheme and embedding - I assume the only way to do
> >> >> this is from inside the interpreter? i.e. there is no magic
> >> >> asynchronous
> >> >> version of scheme_eval_string which can be stopped.
> >> >>
> >> >> cheers,
> >> >>
> >> >> dave
> >> >>
> >> >> http://www.pawfal.org/dave/
> >> >>
> >> >> _________________________________________________
> >> >>   For list-related administrative tasks:
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> >> >>
> >> >
> >>
> >>
> >> http://www.pawfal.org/dave/
> >>
> >>
> > _________________________________________________
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>
>