(test (+ 1 2 3))

(define $sample (lambda [$xs] (nth (pure-rand 1 (length xs)) xs)))

(sample {1 2 3 4 5 6 7 8 9 10})

(define $fib-fast
   (match-lambda integer
     {[,0 0]
      [(& ?(lt? $ 0) $n)
        (if (even? n)
          (neg(fib-fast (neg n)))
          (fib-fast (neg n)))]
      [$n
        (letrec {[$fib-fast-iter (lambda [$a $b $p $q $c]
           (if (lt? c 2)
             (+ (* a p) (* b q))
             (let {[$a' (if (odd? c) (+ (* a p) (* b q)) a)]
                   [$b' (if (odd? c) (+ (* a q) (* b q) (* b p)) b)]
                   [$p' (+ (* p p) (* q q))]
                   [$q' (* (+ (* 2 p) q) q)]
                   [$c' (quotient c 2)]}
               (fib-fast-iter a' b' p' q' c'))))]}
         (fib-fast-iter 0 1 0 1 n))]}))

(test (map fib-fast (between -10 10)))

(fib-fast 100)

(define $sample #f);;再定義

(sample {1 2 3 4 5 6 7 8 9 10})