1 665c255d 2023-08-04 jrmu (define (non-num-members as)
 2 665c255d 2023-08-04 jrmu   (filter (lambda (x) (not (number? x)))
 3 665c255d 2023-08-04 jrmu 	  as))
 4 665c255d 2023-08-04 jrmu (define (num-members as)
 5 665c255d 2023-08-04 jrmu   (filter number? as))
 6 665c255d 2023-08-04 jrmu (define (more-than-one-number? as)
 7 665c255d 2023-08-04 jrmu   (let ((nums (num-members as)))
 8 665c255d 2023-08-04 jrmu     (if (or (null? nums) (null? (cdr nums)))
 9 665c255d 2023-08-04 jrmu 	false
10 665c255d 2023-08-04 jrmu 	true)))
11 665c255d 2023-08-04 jrmu (define (zero-is-the-only-number? as)
12 665c255d 2023-08-04 jrmu   (let ((nums (num-members as)))
13 665c255d 2023-08-04 jrmu     (if (null? nums)
14 665c255d 2023-08-04 jrmu 	false
15 665c255d 2023-08-04 jrmu 	(and (= (car nums) 0) (null? (cdr nums))))))
16 665c255d 2023-08-04 jrmu 
17 665c255d 2023-08-04 jrmu (define (make-sum . as)
18 665c255d 2023-08-04 jrmu   (cond ((null? as) 0)
19 665c255d 2023-08-04 jrmu 	((null? (cdr as)) (car as))
20 665c255d 2023-08-04 jrmu 	((null? (non-num-members as)) (apply + as))
21 665c255d 2023-08-04 jrmu 	((more-than-one-number? as)
22 665c255d 2023-08-04 jrmu 	 (apply make-sum
23 665c255d 2023-08-04 jrmu 		(append (non-num-members as)
24 665c255d 2023-08-04 jrmu 			(list (apply + (num-members as))))))
25 665c255d 2023-08-04 jrmu 	((zero-is-the-only-number? as)
26 665c255d 2023-08-04 jrmu 	 (apply make-sum (non-num-members as)))
27 665c255d 2023-08-04 jrmu 	(else (append '(+) as))))
28 665c255d 2023-08-04 jrmu (define (make-product . ms)
29 665c255d 2023-08-04 jrmu   (cond ((null? ms) 1)
30 665c255d 2023-08-04 jrmu 	((null? (cdr ms)) (car ms))
31 665c255d 2023-08-04 jrmu 	((null? (non-num-members ms)) (apply * ms))
32 665c255d 2023-08-04 jrmu 	((more-than-one-number? ms)
33 665c255d 2023-08-04 jrmu 	 (apply make-product
34 665c255d 2023-08-04 jrmu 		(append (non-num-members ms)
35 665c255d 2023-08-04 jrmu 			(list (apply * (num-members ms))))))
36 665c255d 2023-08-04 jrmu 	((zero-is-the-only-number? ms) 0)
37 665c255d 2023-08-04 jrmu 	((one-is-the-only-number? ms)
38 665c255d 2023-08-04 jrmu 	 (apply make-product (non-num-members ms)))
39 665c255d 2023-08-04 jrmu 	(else (append '(*) ms))))
40 665c255d 2023-08-04 jrmu 
41 665c255d 2023-08-04 jrmu 
42 665c255d 2023-08-04 jrmu (define (augend s)
43 665c255d 2023-08-04 jrmu   (apply make-sum (cddr s)))
44 665c255d 2023-08-04 jrmu (define (multiplicand p)
45 665c255d 2023-08-04 jrmu   (apply make-product (cddr p)))