rotten news relay - comp.lang.lisp - Re: Simple recursive functions in Lisp

Subject: Re: Simple recursive functions in Lisp
From: B. Pym
Newsgroups: comp.lang.lisp
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Date: Sun, 14 Jul 2024 19:46 UTC

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From: Nobody447095@here-nor-there.org (B. Pym)
Newsgroups: comp.lang.lisp
Subject: Re: Simple recursive functions in Lisp
Date: Sun, 14 Jul 2024 19:46:50 -0000 (UTC)
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Pascal Bourguignon wrote:

> (defun sum (list)
> (loop :for x :in list :sum x))

Gauche Scheme

(define (sum lst) (fold + 0 lst))

(sum '(1 3 5 7 9))
===>
25

Subject: Re: Simple recursive functions in Lisp
From: B. Pym
Newsgroups: comp.lang.lisp
Organization: A noiseless patient Spider
Date: Sun, 14 Jul 2024 19:56 UTC
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From: Nobody447095@here-nor-there.org (B. Pym)
Newsgroups: comp.lang.lisp
Subject: Re: Simple recursive functions in Lisp
Date: Sun, 14 Jul 2024 19:56:39 -0000 (UTC)
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B. Pym wrote:

> Pascal Bourguignon wrote:
>
> > (defun sum (list)
> > (loop :for x :in list :sum x))
>
> Gauche Scheme
>
> (define (sum lst) (fold + 0 lst))
>
> (sum '(1 3 5 7 9))
> ===>
> 25

Pascal Bourguignon wrote:

> >> Of course, since LOOP is a higher level abstraction. You should
> >> compare with this iterative form:
> >>
> >> (defun sum (list)
> >> (do ((current list (cdr current))
> >> (sum 0))
> >> ((null current) sum)
> >> (setf sum (+ sum (car current)))))

Better:

(define (sum lst)
(do ((xs lst (cdr xs))
(res 0 (+ res (car xs))))
((null? xs) res)))

A is for Apple. -- Hester Pryne

comp / comp.lang.lisp / Re: Simple recursive functions in Lisp

Subject	Author
Re: Simple recursive functions in Lisp	B. Pym
Re: Simple recursive functions in Lisp	B. Pym