[plt-scheme] module-based language and defining primitives?

>> Somehow, the inner definition of accumulate is being bound to the one
>> that's built into Simply Scheme; that is, I'm seeing let vs letrec
>> behavior on definitions.
>
> If Simply Scheme is a module-based language in DrScheme, I think you
> can tell DrScheme to use `namespace-require/copy' instead of `require',
> which avoids this kind of confusion.

Excellent!  That fixes it.  I'll send an updated plt file to Jacob 
immediately.