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From: "B. Pym" <Nobody447095@here-nor-there.org>
Newsgroups: comp.lang.lisp,comp.lang.scheme
Subject: Re: Lisp newbie needs help
Date: Thu, 29 Aug 2024 09:04:42 -0000 (UTC)
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> (defun my-test ()
>    (loop for number = (1+ (random 6))
>          as sum = number then (+ sum number)
>          until (= number 1)
>          do (format t "~&~D thrown. Sum: ~D" number sum)
>          finally (format t "~&One thrown.")))

Gauche Scheme

(use srfi-1)  ;; unfold
(use srfi-27) ;; random-integer

(define (my-test)
  (fold
    (^(n sum) (print n " thrown.  Sum: " (inc! sum n)) sum)
    0
    (cdr (unfold zero? ($ + 1 $) (^_ (random-integer 6)) -1)))
  (print "One thrown."))


gosh> (my-test)
2 thrown.  Sum: 2
2 thrown.  Sum: 4
6 thrown.  Sum: 10
One thrown.

gosh> (my-test)
One thrown.


Explanation of "unfold":

Function: unfold end-test key gen-next-seed seed :optional tail-gen

(unfold zero? (lambda(n) (+ 800 n)) (lambda(n) (- n 1)) 7)
  ===>
(807 806 805 804 803 802 801)

(unfold zero? (lambda(n) (+ 800 n)) (lambda(n) (- n 1)) 7
  (lambda(n) (list "The number" n "ended the unfolding.")))
  ===>
(807 806 805 804 803 802 801 "The number" 0 "ended the unfolding.")