(let ((sum 0)
      (ints '()))
  (loop for pkg in (list-all-packages)
        do (do-symbols (s pkg)
                       (when (and (boundp s)
                                  (integerp (symbol-value s)))
                            (push s ints)
                            (incf sum (symbol-value s)))))
  (format t "there are ~d integer variables adding up to ~d~%"
          (length ints) sum))