Guile Scheme脚本教程加载脚本

Question

我正在尝试学习一点Guile Scheme，我正在gnu: Scriping Examples

查看教程

目前我有以下代码：

modules.scm：

#!/usr/bin/env sh
exec guile -l fact.scm -e '(@ (my-module) main)' -s "$0" "$@"
!#

;; Explanation:
;; -e (my-module)
;; If run as a script run the `my-module` module's `main`.
;; (Use `@@` to reference not exported procedures.)
;; -s
;; Run the script.

(define-module (my-module)
  #:export (main))

;; Create a module named `fac`.
;; Export the `main` procedure as part of `fac`.

(define (n-choose-k n k)
  (/ (fact n)
     (* (fact k)
        (fact (- n k)))))

(define (main args)
  (let ((n (string->number (cadr args)))
        (k (string->number (caddr args))))
    (display (n-choose-k n k))
    (newline)))

fact.scm

#!/usr/local/bin/guile \
-e main -s
!#

;; How to run this program?
;; Example:
;; guile -e main -s factorial-script.scm 50
;; Explanation:
;; -e specifies the procedure to run
;; -s specifies to run this as a script
;; 50 is the number we take as input to the script

(define (fact n)
  (if (zero? n) 1
      (* n (fact (- n 1)))))

(define (main args)
  (display (fact (string->number (cadr args))))
  (newline))

我使用chmod +x modules.scm使我的主脚本可执行，然后我尝试运行脚本：./modules.scm 10 3（应该是120），但是我收到错误：

Backtrace:
           4 (apply-smob/1 #<catch-closure 119cb80>)
In ice-9/boot-9.scm:
    705:2  3 (call-with-prompt ("prompt") #<procedure 11aa8e0 at ice-9/eval.scm:330:13 ()> #<procedure default-prom…>)
In ice-9/eval.scm:
    619:8  2 (_ #(#(#<directory (guile-user) 1233140>)))
In /home/xiaolong/development/Guile/scripting/./modules.scm:
    26:13  1 (main _)
     18:0  0 (n-choose-k _ _)

/home/xiaolong/development/Guile/scripting/./modules.scm:18:0: In procedure n-choose-k:
In procedure module-lookup: Unbound variable: fact

所以看起来虽然我正在加载fact，但fact.scm过程不会被加载。我也尝试将fact.scm重命名为fact，如同教程所有，并更改了在shebang行之后加载脚本的参数，但结果相同。

教程错了，还是我忽略了一些简单的东西？