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comp / comp.lang.scheme / Re: What to do with (time (length L)) proportional to (length L)

Subject: Re: What to do with (time (length L)) proportional to (length L)
From: B. Pym
Newsgroups: comp.lang.lisp, comp.lang.scheme
Organization: A noiseless patient Spider
Date: Sat, 21 Sep 2024 14:58 UTC

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From: Nobody447095@here-nor-there.org (B. Pym)
Newsgroups: comp.lang.lisp,comp.lang.scheme
Subject: Re: What to do with (time (length L)) proportional to (length L)
Date: Sat, 21 Sep 2024 14:58:42 -0000 (UTC)
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Pascal Costanza wrote:

> (let* ((temp1 (mapcar #'f1 some-list))
> (temp2 (mapcar #'f2 temp1))
> (temp3 (mapcar #'f3 temp2)))
> (mapcar #'f4 temp3))
>
> You could better say:
>
> (loop for elem in some-list
> collect (f4 (f3 (f2 (f1 elem)))))

(map (~> abs sqrt list) '(-4 -9 25))

===>
((2) (3) (5))

Given:

(define-syntax ->>
(syntax-rules ()
[(_ x) x]
[(_ x (y ...) z ...)
(->> (y ... x) z ...)]
[(_ x y z ...)
(->> (y x) z ...)]))

(define-syntax ->
(syntax-rules ()
[(_ x) x]
[(_ x (y more ...) z ...)
(-> (y x more ...) z ...)]
[(_ x y z ...)
(-> (y x) z ...)]))

;; currying
(define-syntax ~>
(syntax-rules ()
[(_ func0 func ...)
(lambda xs (-> (apply func0 xs) func ...))]))

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From: Nobody447095@here-nor-there.org (B. Pym)
Newsgroups: comp.lang.lisp,comp.lang.scheme
Subject: Re: What to do with (time (length L)) proportional to (length L)
Date: Sat, 21 Sep 2024 21:55:53 -0000 (UTC)
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B. Pym wrote:

> > (loop for elem in some-list
> > collect (f4 (f3 (f2 (f1 elem)))))
>
> (map (~> abs sqrt list) '(-4 -9 25))
>
> ===>
> ((2) (3) (5))

(map (~> abs sqrt list (append '(finished))) '(-4 -9 25))
===>
((2 finished) (3 finished) (5 finished))

Subject	Author
Re: What to do with (time (length L)) proportional to (length L)	B. Pym
Re: What to do with (time (length L)) proportional to (length L)	B. Pym