CODEWITHSUNDEEP
schemechicken-scheme
user6253719
user6253719

Reputation:

how to use number in CHICKEN scheme script parameter

Here is my scheme code:

(define (fact n)
  (if (= n 1)
      1
      (* n (fact (- n 1)))))
(define (main args)
  (fact (car args)))

Then i run this code as a script with this command in bash:

csi -ss test.scm 4

However, the interpreter get this error message:

Error: (=) bad argument type: "4"

Call history:

<syntax>      (##core#lambda (n) (define (iter num result) (if (> num n) result (iter (+ num 1) (* result num)))) ...
<syntax>      [fact2] (##core#let ((iter (##core#undefined))) (##core#set! iter (##core#lambda (num result) (if (> num n) ...
<syntax>      [fact2] (##core#begin (##core#set! iter (##core#lambda (num result) (if (> num n) result (iter (+ num 1) (* ...
<syntax>      [fact2] (##core#set! iter (##core#lambda (num result) (if (> num n) result (iter (+ num 1) (* result num))))...
<syntax>      [fact2] (##core#lambda (num result) (if (> num n) result (iter (+ num 1) (* result num))))
<syntax>      [iter] (##core#begin (##core#if (> num n) result (iter (+ num 1) (* result num))))
<syntax>      [iter] (##core#if (> num n) result (iter (+ num 1) (* result num)))
<syntax>      [iter] (> num n)
<syntax>      [iter] (iter (+ num 1) (* result num))
<syntax>      [iter] (+ num 1)
<syntax>      [iter] (* result num)
<syntax>      [fact2] (iter 1 1)
<syntax>      [fact2] (##core#undefined)
<eval>    [main] (fact (car args))
<eval>    [main] (car args)
<eval>    [fact] (= n 1)    <--

I guess the interpreter take the argument 4 as a string, so how to use number in CHICKEN scheme script parameter?

Upvotes: 2

Views: 166

Answers (1)

sjamaan
sjamaan

Reputation: 2292

Try string->number, which is a standard R5RS procedure:

(define (main args)
  (fact (string->number (car args))))

Upvotes: 1

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