Re: How to handle endless loops of Interpreter.eval()?

OK, so it's part of scheme implementation to handle this. Perhaps
someone else might be interested in my solution, so I provide it here.

;; need this for threading
(require-extension (srfi 18))

(define (watch thunk max-running-time timeout-val)
  (let ((t (make-thread thunk)))
    ;; starting thread
    (thread-start! t)

    ;; now lets try to join and collect the join result
    (let ((join-result (thread-join! t max-running-time 'timeout)))

      (if (equal? join-result 'timeout)
	  ;; join did not occur in maximum time so lets return given timeout value
	  (begin
	    (thread-terminate! t)
	    timeout-val)
	  ;; join successful so lets return result of computation
	  join-result))))

On 4/17/06, Matthias Radestock <[email protected]> wrote:
> "Marco Bakera" <[email protected]> writes:
>
> > I have some problem handling endless loops produced by
> > Interpreter.eval(). How is it possible to stop some evaluation of the
> > Interpreter after a certain amount of time - e.g. after some time out
> > occured?
>
> Take a look at the code for sarahbot, the irc bot that, amongst other
> things, contains a sandboxed, resource-constrained Scheme evaluator.
>
> You can find the code in the 'contrib' cvs module, under the 'irc'
> directory.
>
> Regarding your specific query, sarahbot has an |eval-within-n-ms|
> procedure, defined in contrib/irc/scheme/sarah/plugins/scheme.scm.
>
>
> Matthias.
>
>


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