<html><head></head><body>Sweet. I'll try that out when I get back to the machine tomorrow. Thanks for the speedy help! Best, jmj -- Sent from my Android phone with K-9 Mail. <div class="gmail_quote">Robby Findler <robby@eecs.northwestern.edu> wrote:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"> <pre style="white-space: pre-wrap; word-wrap:break-word; font-family: monospace">On Thu, Feb 9, 2012 at 9:12 PM, Eli Barzilay <eli@barzilay.org> wrote: > The other way is what gets you what you want: you need to use > `sandbox-namespace-specs' to make the sandbox share an instance of the > necessary modules between your own code and the sandbox, so that > structs in the sandbox are the same type as your own. Here's a quick > example: > > #lang racket > (require racket/sandbox 2htdp/image) > (define ev > (parameterize ([sandbox-namespace-specs > (list make-base-namespace '2htdp/image)]) > (make-evaluator 'racket #:requires '(2htdp/image)))) > (image? (ev '(rectangle 2 2 'solid 'blue))) This is what I meant by "complex (fiddling with namespaces)" but I see that happily it isn't complex and the sandbox happily does the fiddling for you. Robby </pre></blockquote></div></body></html>