CLCS

Examples of for-as-on-list subclause

;; Collect successive tails of a list.
 (loop for sublist on '(a b c d)
       collect sublist)
⇒  ((A B C D) (B C D) (C D) (D))

;; Print a list by using destructuring with the loop keyword ON.
 (loop for (item) on '(1 2 3)
       do (print item))
 |>  1 
 |>  2 
 |>  3 
⇒  NIL