From: Paul Eggert <eggert@cs.ucla.edu>
To: Pip Cet <pipcet@gmail.com>
Cc: "Mattias Engdegård" <mattiase@acm.org>, emacs-devel@gnu.org
Subject: Re: Bug#38708: eq vs eql in byte-compiled code
Date: Tue, 31 Dec 2019 09:38:18 -0800 [thread overview]
Message-ID: <8cd1b5b2-b94e-ce64-0d70-c1b8b012d685@cs.ucla.edu> (raw)
In-Reply-To: <CAOqdjBc1YB5D2GHkJ4mf50HebdRa-hOUJr5jthKphu3-k87vOQ@mail.gmail.com>
On 12/31/19 7:07 AM, Pip Cet wrote:
> the reason I would prefer not
> to see it installed on the Emacs 27 branch, is that the apparent
> behavior of eq will change in ways that seem paradoxical at first.
One possible compromise would be to duplicate only bignums in the emacs-27
branch, while reserving flonum deduplication for the master branch. This would
help a bit with now-incorrect code that uses eq to compare bignum values, while
not introducing flonum "paradoxes".
> Another option might be to deduplicate constants before optimizing
> forms such as (eq 1.0 1.0). That would be more work, but would also
> avoid the problem.
How about going a bit further, and globally deduplicating all flonums and
bignums that result from low-level text-to-number conversion and module imports?
That conversion is slow and/or rare already, and if we're lucky deduplication
wouldn't make things noticeably slower and wouldn't be much work.
next prev parent reply other threads:[~2019-12-31 17:38 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-31 15:07 Bug#38708: eq vs eql in byte-compiled code Pip Cet
2019-12-31 15:51 ` Andrea Corallo
2019-12-31 16:05 ` Mattias Engdegård
2019-12-31 17:38 ` Paul Eggert [this message]
2020-01-01 12:38 ` Mattias Engdegård
2020-01-02 8:38 ` Paul Eggert
2020-01-02 17:26 ` Mattias Engdegård
2020-01-04 19:55 ` Stefan Monnier
2020-01-22 10:56 ` Mattias Engdegård
2020-01-25 0:59 ` Paul Eggert
2020-01-01 15:45 ` Stefan Monnier
2020-01-02 7:52 ` Paul Eggert
2020-01-02 12:27 ` Pip Cet
2020-01-02 23:12 ` Paul Eggert
2020-01-02 13:48 ` Eli Zaretskii
2020-01-04 18:54 ` Stefan Monnier
2020-01-04 19:33 ` Paul Eggert
2020-01-04 19:49 ` Stefan Monnier
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