[racket] Modifying bindings in parent environment

At Sun, 8 Aug 2010 21:59:41 -0400,
Joe Snikeris wrote:
> Is there a way for a procedure to modify bindings in it's parent
> environment?  I suppose the technique would be similar to passing a
> C-style pointer to the procedure.

Boxes would probably give you what you want.

http://docs.racket-lang.org/guide/boxes.html

Vincent