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From: "B. Pym" <Nobody447095@here-nor-there.org>
Newsgroups: comp.lang.lisp
Subject: Re: CL: Processing more than one element of a sequence at a time?
Date: Mon, 19 Aug 2024 01:50:18 -0000 (UTC)
Organization: A noiseless patient Spider
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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))

newLISP

(apply
  (fn (result a b) (push (cons a b) result -1))
  (cons '() '(f 3  g 4  h 5))
  3  ;; How many items to process at a time.
)

((f 3) (g 4) (h 5))