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From: "B. Pym" <Nobody447095@here-nor-there.org>
Newsgroups: comp.lang.lisp,comp.lang.scheme
Subject: Re: List of digits->number
Date: Sat, 21 Sep 2024 13:59:34 -0000 (UTC)
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Frank Buss wrote:

> (defun split-backward (number &optional (base 10))
>   (loop while (< 0 number) collect
>         (multiple-value-bind (quotient remainder) (floor number base)
>           (setf number quotient)
>           remainder)))
> 
> LOOP is ok, but I wonder if there is a more elegant contruct like REDUCE
> for the opposite concept for building a list. Building the list should not
> need more program code characters than reducing the list.

Testing:

* (split-backward 1984)

(4 8 9 1)


Gauche Scheme

(use srfi-1) ; unfold

(unfold zero? (cut mod <> 10) (cut quotient <> 10) 1984)
  ===>
(4 8 9 1)