1.1.2 Differences between LOOP and DO

1.1.2.1 Example 1

;;; These functions remove duplicates from a list and return a 
;;; copy of the list with duplicates removed. The Loop Facility 
;;; code takes care of many iteration details and is more compact
;;; than the code that uses the DO macro.
(defun rem-dups-loop (list)                  ; Use Loop Facility 
  (loop for item in list                     ; constructs.
        unless (member item result)
          collect item into result
        finally (return result)))

(defun rem-dups-do (list)                    ; Use the DO macro.
  (let ((result nil))    
    (do* ((tail list (cdr tail))
          (item (car tail) (car tail)))
        ((null tail) (nreverse result))
      (unless (member item result)
        (push item result)))))

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