; Double frying the baked tomatoes (nested atom duplication)
; ------------------------------
; The Little Lisper 3rd Edition
; Chapter 6
; Exercise 3
; Common Lisp
; http://t...content-available-to-author-only...r.com/thelittlelisper
; http://t...content-available-to-author-only...t.com/2010/06/little-lisper-chapter-6-oh-my-gawd-its.html
; http://t...content-available-to-author-only...t.com/2010/06/little-lisper.html
; ------------------------------
(setf l1 '((fried potatoes)(baked (fried)) tomatoes))
(setf l2 '(((chili) chili (chili))))
(setf l3 '())
(setf lat1 '(chili and hot)) 
(setf lat2 '(baked fried)) 
(setf a 'fried)
; ------------------------------

(defun double (a lat)
  (cond
   ((null lat) '())
   ((eq (car lat) a)(cons a lat))
   (t (cons (car lat)
            (double a (cdr lat))))))

(print (double 'bob '(bob the builder)))

(defun notatom (lat)
  (not (atom lat)))

(defun double* (a lat)
  (cond
   ((null lat) '())
   ((notatom (car lat))
    (cons (double* a (car lat))
          (double* a (cdr lat))))
   ((eq (car lat) a)(cons a lat))
   (t (cons (car lat)
            (double* a (cdr lat))))))

(print (double* 'bob '(bob the builder)))
;(BOB BOB THE BUILDER)

(print (double* 'bob '((bob) the builder)))
;((BOB BOB) THE BUILDER)

(print (double* a l1))
;((FRIED FRIED POTATOES) (BAKED (FRIED FRIED)) TOMATOES)

(print (double* a l2))
;(((CHILI) CHILI (CHILI)))

(print (double* a lat2))
;(BAKED FRIED FRIED)