Having been away from CFFI for several months, I thought I'd ask: what happened to callback-lambda? James Bielman implemented an interim solution, but it never made its way into mainline CFFI and I think has bitrotted by now. Any particular reason why?
As for me, a working callback-lambda under SBCL (and later ECL) would be a MAJOR win. Even more so if I could avoid memory leaks by being able to delete callbacks when they're no longer needed.
--J.