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From: "B. Pym" <Nobody447095@here-nor-there.org>
Newsgroups: comp.lang.lisp,comp.lang.scheme
Subject: Re: Learning Lisp in Linux?
Date: Wed, 28 Aug 2024 00:49:14 -0000 (UTC)
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Pascal Costanza wrote:

> > I'm not advocating tail-recursion instead of specialized iteration
> > mechanisms closer to the problem domain.  I'm just saying tail-
> > recursion code isn't anywhere as low-level as you're making it up to
> > be.
> 
> It actually is, and your posting below shows it very nicely.
> 
> >> Here is a nice example using loop:
> >>
> >> (loop for (key value) on property-list by #'cddr
> >>        unless (member key excluded-keys)
> >>        append (list key value)) ; [1]
> 
> As a function:
> 
> (defun filter (excluded-keys property-list)
>    (loop for (key value) on property-list by #'cddr
>          unless (member key excluded-keys)
>          nconc (list key value)))
> 
>  > (filter '(c d) '(a 1 b 2 b 3 c 4 d 5 c 6))
> (A 1 B 2 B 3)
> 
> The result is a correct property list

Gauche Scheme
 
(define (remove-props bad-keys prop-list)
  (concatenate
    (remove (^p (member (car p) bad-keys))
      (slices prop-list 2))))

(remove-props '(c d) '(a 1 b 2 b 3 c 4 d 5 c 6))
  ===>
(a 1 b 2 b 3)