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devel / comp.lang.lisp / Multivalue tail recursion?

Multivalue tail recursion?

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https://www.rocksolidbbs.com/devel/article-flat.php?id=16837&group=comp.lang.lisp#16837

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From: No_spamming@noWhere_7073.org (Robert L.)
Newsgroups: comp.lang.lisp
Subject: Multivalue tail recursion?
Date: Sun, 13 Feb 2022 03:35:52 -0000 (UTC)
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by: Robert L. - Sun, 13 Feb 2022 03:35 UTC

> > I would probably do something like this instead:
> >
> > (defun first-n (n list)
> > (loop for i below n for (a . d) on list
> > collect a into x
> > finally (return (values x d))))
>
> Niiiiiiice.

Gauche, Chicken, or Racket

(use srfi-1) ;; split-at for Chicken

(split-at '(a b c d e) 2)
===>
(a b)
(c d e)

Re: Multivalue tail recursion?

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From: No_spamming@noWhere_7073.org (Robert L.)
Newsgroups: comp.lang.lisp
Subject: Re: Multivalue tail recursion?
Date: Sun, 13 Feb 2022 07:30:43 -0000 (UTC)
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by: Robert L. - Sun, 13 Feb 2022 07:30 UTC

On 2/12/2022, Robert L. wrote:

> > > I would probably do something like this instead:
> > >
> > > (defun first-n (n list)
> > > (loop for i below n for (a . d) on list
> > > collect a into x
> > > finally (return (values x d))))
> >
> > Niiiiiiice.
>
> Gauche, Chicken, or Racket
>
> (use srfi-1) ;; split-at for Chicken
>
> (split-at '(a b c d e) 2)
> ===>
> (a b)
> (c d e)
>

Gauche Scheme:

(define (first-n n xs . ys)
(dotimes (n) (push! ys (pop! xs)))
(values (reverse ys) xs))

Subject	Author
Multivalue tail recursion?	Robert L.
Re: Multivalue tail recursion?	Robert L.