r% returns pointers, r decodes the result
RCL> (r "seq" 1 5 :length 3)
(1.0d0 3.0d0 5.0d0)
RCL> (r% "print" (r% "summary" '(3 21 12 31 9 17 25 29 5 14)))
R# Min. 1st Qu. Median Mean 3rd Qu. Max.
R# 3.00 9.75 15.50 16.60 24.00 31.00
#.(SB-SYS:INT-SAP #X06690168)
RCL> (r "plot")
R! Error in function (x, y, ...) : argument "x" is missing, with no default
; Evaluation aborted
(defun plot-example ()
  (flet ((list-symbols (&optional package &aux symbols)
           (mapcar #'symbol-name (if package 
                                     (do-symbols (s package symbols) (push s symbols))
                                     (do-all-symbols (s symbols) (push s symbols)))))) 
    (let ((lengths-cl (mapcar #'length (list-symbols "CL")))
          (lengths-all (mapcar #'length (list-symbols))))
      (r:with-device ("/tmp/symbol-length" :pdf)
        (r:r "hist" lengths-cl :breaks "scott"
                   :ylab "number" :xlab "symbol length" :main "symbols in COMMON-LISP")
        (r:r "hist" lengths-all :breaks "scott"
                   :ylab "number" :xlab "symbol length" :main "symbols in all packages")))))
(plot-example) => symbol-length.pdf