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From: Kaz Kylheku <643-408-1753@kylheku.com>
Newsgroups: comp.lang.lisp,comp.lang.scheme
Subject: Re: Loopiness
Date: Fri, 27 Sep 2024 01:13:00 -0000 (UTC)
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On 2024-09-26, B. Pym <Nobody447095@here-nor-there.org> wrote:
>>   (loop for x in things
>>         when (foo-p x) collect x into foos
>>         when (bar-p x) collect x into bars
>>         when (and (foo-p x) (bar-p x)) collect x into both
>>         finally (return (values foos bars both)))
>
> It's shorter in Gauche Scheme.

It's five physical nonblank lines of code.

>
>    (define things '(0 3 -5 4 9 -7 6 8))
>
> 1: (let@ (() odds posi both)
> 2:  (dolist (x things)
> 3:    (when (odd? x) (push! odds x))
> 4:    (when (positive? x) (push! posi x)
> 5:      (when (odd? x) (push! both x))))
> 6:  (values odds posi both))
>
> (-7 9 -5 3)
> (8 6 9 4 3)
> (9 3)
>
> Given:
>
> 7: (define-macro let@
> 8:   (lambda (lets . exprs)
> 9:     (let ((lets lets)
> 10:          (let-pairs '()))
> 11:    (if (list? lets)
> 12:      (while (pair? lets)
> 13:        (let ((x (pop! lets)))
> 14:          (cond
> 15:            ((not (symbol? x))
> 16:             (while (pair? lets)
> 17:               (push! let-pairs (list (pop! lets) x))))
> 18:            ((null? lets) (push! let-pairs (list x 0)))
> 19:            (#t (push! let-pairs (list x (pop! lets)))))))
> 20:      (set! let-pairs `((,lets 0))))
> 21:    `(let* ,(reverse let-pairs)
> 22:       ,@exprs))))

How is twenty-two nonblank lines shorter than five?

You are clearly not well.