RetroBBS - comp.lang.lisp - .Re: CL: Processing more than one element of a sequence at a time?

.Re: CL: Processing more than one element of a sequence at a time?

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https://www.rocksolidbbs.com/devel/article-flat.php?id=16903&group=comp.lang.lisp#16903

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From: No_spamming@noWhere_7073.org (Robert L.)
Newsgroups: comp.lang.lisp
Subject: .Re: CL: Processing more than one element of a sequence at a time?
Date: Sun, 20 Feb 2022 01:59:53 -0000 (UTC)
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by: Robert L. - Sun, 20 Feb 2022 01:59 UTC

Frode V. Fjeld wrote:

> Raffaele Ricciardi <rfflrccrd@gmail.com> writes:
>
> > in CL, is there an idiomatic way to process more than one element of a
> > sequence at a time?
>
> Yes: (loop for (a b) on list by #'cddr collect (cons a b))
>
> Or without LOOP, I'd do:
>
> (do ((a (pop list) (pop list))
> (b (pop list) (pop list))
> (result nil))
> ((null list) (reverse result))
> (push (cons a b) result))

Gauche Scheme:

(use srfi-1) ;; unfold

(define xs '(k 6 u 8 s 3))

(unfold null? (cut take <> 2) cddr xs)
===>
((k 6) (u 8) (s 3))

Where are the calculations that go with a calculated risk?

devel / comp.lang.lisp / .Re: CL: Processing more than one element of a sequence at a time?

devel / comp.lang.lisp / .Re: CL: Processing more than one element of a sequence at a time?

Subject	Author
.Re: CL: Processing more than one element of a sequence at a time?	Robert L.