From: Lynn Winebarger <owinebar@gmail.com>
To: Richard Stallman <rms@gnu.org>
Cc: Alan Mackenzie <acm@muc.de>,
ulm@gentoo.org, emacs-devel <emacs-devel@gnu.org>
Subject: Re: Why have a #if .... #else .... #endif construct in Emacs Lisp, when we could make the existing code DTRT unchanged?
Date: Tue, 5 Sep 2023 07:26:01 -0400 [thread overview]
Message-ID: <CAM=F=bAaRHKyKZfJMdt5UaCQpa+d2AenauTRdOg3YQ_0kZHVnw@mail.gmail.com> (raw)
In-Reply-To: <E1qdJxZ-0005QO-Q2@fencepost.gnu.org>
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On Mon, Sep 4, 2023, 8:30 PM Richard Stallman <rms@gnu.org> wrote:
> [[[ To any NSA and FBI agents reading my email: please consider ]]]
> [[[ whether defending the US Constitution against all enemies, ]]]
> [[[ foreign or domestic, requires you to follow Snowden's example. ]]]
>
> > How about making the byte compiler recognize the construct
>
> > (if (< emacs-major-version NUMBER) ...)
>
> > and do this optimization on it?
>
> People seem not to have considered this seriously, but I have not seen
> any serious discussion of a drawback. What flaw or drawback do people
> see in it? It should optimize the existing the existing code with no
> change at all. Isn't that just perfect?
>
Since byte-compiled files are not versioned, emacs-major-version is not
really a constant, so constant-folding isn't correct.
For example, loading a file in version 29 that was byte-compiled by version
28 (or earlier) may not be the same as byte-compiling the file with version
29.
Lynn
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next prev parent reply other threads:[~2023-09-05 11:26 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-28 19:37 Why shouldn't we have a #if .... #else .... #endif construct in Emacs Lisp? Alan Mackenzie
2023-08-28 19:47 ` Ulrich Mueller
2023-08-28 20:06 ` Alan Mackenzie
2023-08-28 21:01 ` Ulrich Mueller
2023-08-28 21:46 ` Alan Mackenzie
2023-08-31 2:07 ` Richard Stallman
2023-08-31 7:50 ` Alan Mackenzie
2023-09-04 1:34 ` Richard Stallman
2023-09-04 10:50 ` Alan Mackenzie
2023-09-04 11:02 ` tomas
2023-09-04 15:19 ` Emanuel Berg
2023-09-04 18:57 ` tomas
2023-09-06 0:58 ` Richard Stallman
2023-09-06 0:58 ` Richard Stallman
2023-09-06 7:28 ` Andreas Schwab
2023-09-06 9:31 ` Alan Mackenzie
2023-09-06 9:56 ` Alan Mackenzie
2023-09-09 0:39 ` Richard Stallman
2023-09-09 10:32 ` Ihor Radchenko
2023-09-10 0:22 ` Richard Stallman
2023-09-10 8:36 ` Ihor Radchenko
2023-09-13 23:53 ` Richard Stallman
2023-09-20 12:59 ` Ihor Radchenko
2023-09-05 0:30 ` Why have a #if .... #else .... #endif construct in Emacs Lisp, when we could make the existing code DTRT unchanged? Richard Stallman
2023-09-05 0:41 ` Emanuel Berg
2023-09-08 17:54 ` Emanuel Berg
2023-09-05 4:37 ` tomas
2023-09-05 5:53 ` Ihor Radchenko
2023-09-05 6:28 ` tomas
2023-09-05 11:06 ` Adam Porter
2023-09-05 11:26 ` Lynn Winebarger [this message]
2023-09-05 14:11 ` Alan Mackenzie
2023-09-08 1:01 ` Richard Stallman
2023-09-08 2:45 ` Po Lu
2023-09-10 0:24 ` Richard Stallman
2023-09-05 8:14 ` Why shouldn't we have a #if .... #else .... #endif construct in Emacs Lisp? Ulrich Mueller
2023-08-28 19:53 ` Emanuel Berg
2023-08-29 9:19 ` Alan Mackenzie
2023-08-29 10:36 ` João Távora
2023-08-29 11:09 ` Ihor Radchenko
2023-08-29 11:20 ` João Távora
2023-08-30 20:48 ` Sean Whitton
2023-08-30 20:59 ` João Távora
2023-09-02 23:12 ` Stefan Monnier via Emacs development discussions.
2023-09-03 0:18 ` Emanuel Berg
2023-09-03 12:27 ` João Távora
2023-08-29 12:54 ` Philip Kaludercic
2023-08-29 13:23 ` Alan Mackenzie
2023-09-02 23:09 ` Stefan Monnier via Emacs development discussions.
2023-08-29 16:28 ` LdBeth
2023-08-29 20:09 ` Stefan Kangas
2023-08-30 10:31 ` Alan Mackenzie
2023-08-30 17:36 ` Stefan Kangas
2023-08-30 18:03 ` Alan Mackenzie
2023-08-30 18:17 ` Stefan Kangas
2023-09-02 15:06 ` Alan Mackenzie
2023-09-02 15:17 ` Eli Zaretskii
2023-09-02 19:43 ` Alan Mackenzie
2023-09-03 4:42 ` Eli Zaretskii
2023-09-03 10:48 ` Alan Mackenzie
2023-09-03 11:02 ` Eli Zaretskii
2023-09-03 13:24 ` Alan Mackenzie
2023-09-02 19:20 ` Philip Kaludercic
2023-09-02 19:37 ` Stefan Kangas
2023-09-02 19:58 ` Alan Mackenzie
2023-09-04 11:12 ` Lynn Winebarger
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