Mark Polesky:
;; Hi.
;;
;; How can I change the following code so that
;; it returns "2 0.25 0.3333"? That is: return
;; integers without decimal point, otherwise
;; round to as many decimal places as needed,
;; but not more than 4.
(let ((a 2.0)
(b 1/4)
(c 1/3))
(format #t "~&~a ~a ~a" a b c))
;; After some experimenting, I found the
;; following solution, but I'd rather not have
;; to deal with all the incessant quasiquote
;; and unquote stuff. Is there a more elegant
;; solution?
;;
;; Thanks in advance.
;; - Mark
(define (set-precision n)
(let* ((max-decimals 4)
(k (expt 10.0 max-decimals)))
(if (number? n)
(if (integer? n)
(inexact->exact n)
(/ (round (* n k))
k))
n)))
(define (my-format bool string list-of-nums)
(apply format bool string (map set-precision list-of-nums)))
(let ((a 2.0)
(b 1/4)
(c 1/3))
(my-format #t "~&~a ~a ~a" `(,a ,b ,c)))
Yes:
(let ((a 2.0)
(b 1/4)
(c 1/3))
(my-format #t "~&~a ~a ~a" (list a b c)))
But better:
(define (my-format bool string . list-of-nums)
(apply format bool string (map set-precision list-of-nums)))
(let ((a 2.0)
(b 1/4)
(c 1/3))
(my-format #t "~&~a ~a ~a" a b c))
I would also think that 'format' has an option
to do this directly without calling 'set-precision',
but I don't know...
