[racket-dev] printing images in REPL

From: Shriram Krishnamurthi (sk at cs.brown.edu)
Date: Sat Aug 28 21:23:31 EDT 2010

The value I was returning is whatever kind of object is returned when
you embed an image in the Definitions window.  That is, this was a
pasted, atomic image, not one created by a computation.  I guess
they're not treated the same, but I'm surprised that ASL processing
the Definitions window didn't do the right conversion...

On Thu, Aug 26, 2010 at 8:25 PM, Robby Findler
<robby at eecs.northwestern.edu> wrote:
> At the moment there is a barn-door sized security hole in DrRacket,
> whereby it will take any snip% instance from the user's program and
> just display it in the repl. You can exploit this for Good by making
> the current-print of your language turn some values into snips (like
> images and things). 2htdp/image already does this, so that should just
> work if you return those. Its hard to tell what value Shriram's
> program was returning tho. But if it is a bitmap% object, he just has
> to do
>  (make-object image-snip% ...the-bitmap-goes-here...)
> We will close this hole at some point, when we have a reasonable way
> to allow people to add new kinds of values without the security
> breach.
> Robby
> On Thu, Aug 26, 2010 at 6:17 PM, Jay McCarthy <jay.mccarthy at gmail.com> wrote:
>> From what I can tell, it comes from ensuring that DrRacket shares the
>> htdp/image (or whatever) namespace with the running program so the
>> structs are the same and DrRacket's default renderer is detecting it.
>> I'm not sure how to replicate it though. (I tried for a bit so I could
>> make #lang frtime work.)
>> Jay
>> On Thu, Aug 26, 2010 at 11:55 AM, Shriram Krishnamurthi <sk at cs.brown.edu> wrote:
>>> What is the #lang magic that makes
>>>> (get-image-from-web "http://racket-lang.org/logo.png")
>>> (instantiate (class ...) ...)
>>> show the image rather than just its constructor?
>>> Shriram
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>> --
>> Jay McCarthy <jay at cs.byu.edu>
>> Assistant Professor / Brigham Young University
>> http://teammccarthy.org/jay
>> "The glory of God is Intelligence" - D&C 93
>> _________________________________________________
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>>  http://lists.racket-lang.org/listinfo/dev

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