Function: VARS

Source

(defun vars (match-spec)
  (let ((vars nil))
    (labels ((find-vars (spec)
               (cond
                 ((null spec) nil)
                 ((varsymp spec) (push spec vars))
                 ((consp spec)
                  (find-vars (car spec))
                  (find-vars (cdr spec))))))
      (find-vars match-spec))
    (delete-duplicates vars)))