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* Negative nth index
@ 2024-12-22  5:43 Anand Tamariya
  2024-12-22  7:39 ` Eli Zaretskii
  2024-12-22 10:16 ` Andreas Schwab
  0 siblings, 2 replies; 4+ messages in thread
From: Anand Tamariya @ 2024-12-22  5:43 UTC (permalink / raw)
  To: Emacs Devel

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Should negative index for nth be valid? e.g.
(nth -1 '(1 2)) returns 1

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^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Negative nth index
  2024-12-22  5:43 Negative nth index Anand Tamariya
@ 2024-12-22  7:39 ` Eli Zaretskii
  2024-12-22  9:01   ` Tassilo Horn
  2024-12-22 10:16 ` Andreas Schwab
  1 sibling, 1 reply; 4+ messages in thread
From: Eli Zaretskii @ 2024-12-22  7:39 UTC (permalink / raw)
  To: Anand Tamariya; +Cc: emacs-devel

> From: Anand Tamariya <atamariya@gmail.com>
> Date: Sun, 22 Dec 2024 11:13:18 +0530
> 
> Should negative index for nth be valid? e.g. 
> (nth -1 '(1 2)) returns 1

What does this do in other Lisps?



^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Negative nth index
  2024-12-22  7:39 ` Eli Zaretskii
@ 2024-12-22  9:01   ` Tassilo Horn
  0 siblings, 0 replies; 4+ messages in thread
From: Tassilo Horn @ 2024-12-22  9:01 UTC (permalink / raw)
  To: Eli Zaretskii; +Cc: Anand Tamariya, emacs-devel

Eli Zaretskii <eliz@gnu.org> writes:

>> Should negative index for nth be valid? e.g. 
>> (nth -1 '(1 2)) returns 1
>
> What does this do in other Lisps?

In CL, it errors (ditto for nthcdr with negative index).  Same for (nth
'(1 2 3) -1) in Clojure or (list-ref '(1 2 3) -1) in Scheme.

Bye,
Tassilo



^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Negative nth index
  2024-12-22  5:43 Negative nth index Anand Tamariya
  2024-12-22  7:39 ` Eli Zaretskii
@ 2024-12-22 10:16 ` Andreas Schwab
  1 sibling, 0 replies; 4+ messages in thread
From: Andreas Schwab @ 2024-12-22 10:16 UTC (permalink / raw)
  To: Anand Tamariya; +Cc: Emacs Devel

On Dez 22 2024, Anand Tamariya wrote:

> (nth -1 '(1 2)) returns 1

What would (nth -1 '#1=(1 2 . #1#)) return?

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."



^ permalink raw reply	[flat|nested] 4+ messages in thread

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Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2024-12-22  5:43 Negative nth index Anand Tamariya
2024-12-22  7:39 ` Eli Zaretskii
2024-12-22  9:01   ` Tassilo Horn
2024-12-22 10:16 ` Andreas Schwab

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