1 665c255d 2023-08-04 jrmu (define (non-num-members as)
 2 665c255d 2023-08-04 jrmu   (filter (lambda (x) (not (number? x))) as))
 3 665c255d 2023-08-04 jrmu (define (num-members as)
 4 665c255d 2023-08-04 jrmu   (filter number? as))
 5 665c255d 2023-08-04 jrmu (define (more-than-one-number? as)
 6 665c255d 2023-08-04 jrmu   (let ((nums (num-members as)))
 7 665c255d 2023-08-04 jrmu     (if (or (null? nums) (null? (cdr nums)))
 8 665c255d 2023-08-04 jrmu 	#f
 9 665c255d 2023-08-04 jrmu 	#t)))
10 665c255d 2023-08-04 jrmu (define (zero-is-the-only-number? as)
11 665c255d 2023-08-04 jrmu   (let ((nums (num-members as)))
12 665c255d 2023-08-04 jrmu     (if (null? nums)
13 665c255d 2023-08-04 jrmu 	#f
14 665c255d 2023-08-04 jrmu 	(and (= (car nums) 0) (null? (cdr nums))))))
15 665c255d 2023-08-04 jrmu (define (one-is-the-only-number? as)
16 665c255d 2023-08-04 jrmu   (let ((nums (num-members as)))
17 665c255d 2023-08-04 jrmu     (if (null? nums)
18 665c255d 2023-08-04 jrmu 	#f
19 665c255d 2023-08-04 jrmu 	(and (= (car nums) 1) (null? (cdr nums))))))
20 665c255d 2023-08-04 jrmu (define (insert-signs result items sign)
21 665c255d 2023-08-04 jrmu   (cond ((null? items) result)
22 665c255d 2023-08-04 jrmu 	((null? result)
23 665c255d 2023-08-04 jrmu 	 (insert-signs (list (car items)) (cdr items) sign))
24 665c255d 2023-08-04 jrmu 	(else (insert-signs (append result (list sign (car items))) 
25 665c255d 2023-08-04 jrmu 			    (cdr items) sign))))
26 665c255d 2023-08-04 jrmu 
27 665c255d 2023-08-04 jrmu