To answer your question, the parameters to 'awhen would be wrapped up such that they were automatically associated with the place they came from. (Hmm, I guess that's a bit troublesome in itself, since it means they're essentially like Racket syntax objects, which need to be unwrapped to get at their original structure.)

More difficult to resolve: Somehow, the output of 'awhen oughta be wrapped up so that it's associated with the envioronment where 'awhen was defined. (And maybe this should be done more explicitly than it is in that example. Actually, while I was writing the example, I didn't remember this at all.)

In my current design for Penknife macros (toward the top of https://github.com/rocketnia/penknife/blob/1e5f3dd6cd86a2450..., a file in my Penknife draft[1]), both qq and leak are quasiquotes that anaphorically use lexical parameters of the macro call. They both use plainqq, and leak annotates the result so that it corresponds with the caller's namespace, while qq annotates it so it corresponds with the namespace surrounding the macro.

The hard part is that for qq to have a namespace to refer to, Penknife macros capture the local namespace they're defined in. That's not straightforward to translate to Racket; I basically end up making a shadowing namespace data structure at the start of each function call. On the other hand, it's probably sufficient to capture the global namespace. I was kinda just doing this for elegance's sake, since I kinda consider even a file-global namespace to be a local one, with imports as the local variables.

Got all that? I think I may have overexplained minutia this time around. ^^;