Variable *, **, ***
The variables *, **, and *** are maintained by the Lisp read-eval-print loop to save the values of results that are printed each time through the loop.
The value of * is the most recent primary value that was printed, the value of ** is the previous value of *, and the value of *** is the previous value of **.
If several values are produced, * contains the first value only; * contains nil if zero values are produced.
The values of *, **, and *** are updated immediately prior to printing the return value of a top-level form by the Lisp read-eval-print loop. If the evaluation of such a form is aborted prior to its normal return, the values of *, **, and *** are not updated.
(values 'a1 'a2)
(values 'c1 'c2 'c3)
(list * *)
(C1 B A1)
(defun cube-root (x) (expt x 1/3))
(defparameter *a* (cube-root 27.0))
(* * 9.0)
* ≡ (car /)
≡ (car //)
* ≡ (car ///)