如何“定义 - 价值”＆＃39;＆＃39;在for-clause中？

Question

我希望在define-values的{​​{1}}内p两个整数标识符q和for-clause。我可以这样做吗？

for/fold

我得到了：

(define (benchmark x0 ls)
  (let ([primes-generator (all-pairs-gen ls)])
    (for/fold 
        ([failures 0] [f_cost 0] [it_cost 0])
        ([(p q) (primes-generator)]
         [r (pollard (* p q) x0)])
      `((failures (+ failures (if (false? r) 0 (cadr (assq 'factor r)))))
        (it_cost (+ it_cost (cadr (assq 'it_cost r))))
        (f_cost (+ f_cost (cadr (assq 'f_cost r))))))))

(define (all-pairs-gen ls)
  (generator ()
   (for ([i (in-range (length ls))])
     (for ([j (in-range (add1 i) (length ls))])
       (yield (values (list-ref ls i) (list-ref ls j)))))))

EDIT2：

尝试

> (benchmark 2 (list 1 2 3))
result arity mismatch;
 expected number of values not received
  expected: 1
  received: 2
  values...:
   1
   2

得到了：

(define (test2)
  (let ([primes-generator (all-pairs-gen (list 1 2 4))])
    (for/fold ([acc 0])
        ([(p q) (in-producer primes-generator (void))])
      (* p q))))