Ooops. I yanked this new macro out of the use case just before posting everything to CVS, forgetting some of you old Cells hands would likely not update from CVS before trying the use case.
Here is with-c-cache, not found in cells/constructirs.lisp
(defmacro with-c-cache ((fn) &body body) (let ((new (gensym))) `(or (bwhen (,new (progn ,@body)) (funcall ,fn ,new .cache)) .cache)))
kt