1 ;; Use this notation to write a procedure same-parity that takes one or more integers and returns a list of all the arguments that have the same even-odd parity as the first argument. For example,
2 
3 ;; (define (same-parity parity . integers)
4 ;;   (let ((rem (remainder parity 2)))
5 ;;     (define (par ints)
6 ;;       (cond ((null? ints) '())
7 ;; 	    ((= (remainder (car ints) 2) rem) 
8 ;; 	     (cons (car ints)
9 ;; 		   (par (cdr ints))))
10 ;; 	    (else (par (cdr ints))))))
11 ;;   (cons parity (par integers)))
12 
13 ;; par seems not to be in scope in the call at the end
14 
15 
16 (define (same-parity parity . integers)
17   (let ((rem (remainder parity 2)))
18     (define (par ints)
19       (cond ((null? ints) '())
20 	    ((= (remainder (car ints) 2) rem) 
21 	     (cons (car ints)
22 		   (par (cdr ints))))
23 	    (else (par (cdr ints)))))
24     (cons parity (par integers))))
25 
26 
27 (define (test-case actual expected)
28   (load-option 'format)
29   (newline)
30   (format #t "Actual: ~A Expected: ~A" actual expected))
31 
32 (test-case (same-parity 1 2 3 4 5 6 7) '(1 3 5 7))
33 (test-case (same-parity 2 3 4 5 6 7) '(2 4 6))