From: Lars Ingebrigtsen <larsi@gnus.org>
To: "Mattias Engdegård" <mattiase@acm.org>
Cc: 55395@debbugs.gnu.org, Stefan Monnier <monnier@iro.umontreal.ca>
Subject: bug#55395: What does (1 2 3 . #2) mean?
Date: Fri, 13 May 2022 17:22:13 +0200 [thread overview]
Message-ID: <87ilq931ay.fsf@gnus.org> (raw)
In-Reply-To: <4B70C9BE-B784-4B74-A081-7A8B3F8D5136@acm.org> ("Mattias Engdegård"'s message of "Fri, 13 May 2022 13:32:34 +0200")
Mattias Engdegård <mattiase@acm.org> writes:
> It may have made more sense before the switch of cycle-detection algorithm from Floyd to Brent. This can be fixed by hand-coding the list iteration and explicitly remembering the index of the tortoise, but would that be correct? What's the spec?
I don't think I've ever considered #x to be meaningful outside of
print-circle, but I guess if we wanted to have some semantics here, I
think I would have expected the index of the tortoise? But...
> If #N means 'Nth object from the top along the path to the current object, starting at 0' then we should have
>
> (rho 2 3) => (1 2 3 4 5 . #2)
> (list (rho 2 3)) => ((1 2 3 4 5 . #3))
>
> ie, adding the print depth to the index in the list. Do you agree?
I've added Stefan to the CCs; I'm sure he has an opinion.
--
(domestic pets only, the antidote for overdose, milk.)
bloggy blog: http://lars.ingebrigtsen.no
next prev parent reply other threads:[~2022-05-13 15:22 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-13 11:32 bug#55395: What does (1 2 3 . #2) mean? Mattias Engdegård
2022-05-13 15:22 ` Lars Ingebrigtsen [this message]
2022-05-13 17:20 ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2022-05-13 19:54 ` Lars Ingebrigtsen
2022-05-13 20:01 ` Mattias Engdegård
2022-05-14 13:45 ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2022-05-18 14:29 ` Mattias Engdegård
2022-05-18 21:16 ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2022-05-23 14:59 ` Mattias Engdegård
2022-05-13 16:08 ` Andreas Schwab
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