From: Zack Weinberg <zack@codesourcery.com>
Cc: snogglethorpe@gmail.com, emacs-devel@gnu.org, miles@gnu.org
Subject: Re: byte-opt.el addition - optimize list of compile-time constants
Date: Wed, 08 Dec 2004 21:33:43 -0800 [thread overview]
Message-ID: <878y88ox1k.fsf@codesourcery.com> (raw)
In-Reply-To: <874qiwqdo5.fsf-monnier+emacs@gnu.org> (Stefan Monnier's message of "Wed, 08 Dec 2004 23:52:50 -0500")
Stefan Monnier <monnier@iro.umontreal.ca> writes:
> Note that the expression
>
> (list 1 2 (function (lambda () (with-current-buffer))))
>
> can be rejected by the compiler (not enough arguments to the
> with-current-buffer macro) whereas
>
> '(1 2 (function (lambda () (with-current-buffer))))
>
> can't because it's just a quoted constant which just happens to look like
> invalid code.
I'd say that the compiler can and should reject your second example
precisely so that the equivalence of the two forms can be preserved.
Miles Bader <snogglethorpe@gmail.com> writes:
>> Also, in Common Lisp the situation is clearly that the compiler _is_
>> entitled to compile (function ...) wherever it finds it
>
> Can you provide a reference for this? Given that it's quite
> dangerous, I'm skeptical of this claim.
I was going by CLTL/1, which says "The value of function is *always*
the functional interpretation of [its argument]" (emphasis mine).
That's a little ambiguous (although, as standardese goes, pretty damn
clear (my brain may have been warped by the C standard's heinous
ambiguities)).
The most recent edition of the ANSI Common Lisp spec that I can find
online
[http://www.lispworks.com/reference/HyperSpec/Front/Contents.htm] says
basically the same thing, but goes on to observe that function objects
may not appear in quoted literals which are to be processed by
compile-file. I'm not really sure what the implications are. See
<http://www.lispworks.com/reference/HyperSpec/Issues/iss082_w.htm>.
> Note that a possibly safer alternative would be to have the #'
> reader macro expand into something less ambiguous during compilation
> (e.g., a special non-interned symbol), which the byte-compiler could
> then safely interpret inside of constants. This may cause grief for
> somebody that uses #' in a non-traditional way, and _expects_ to see
> (function (lambda ...)), but that may be an acceptable price.
I don't think this is any better than saying that function always
means function, even if not evalled.
zw
next prev parent reply other threads:[~2004-12-09 5:33 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-08 9:21 byte-opt.el addition - optimize list of compile-time constants Zack Weinberg
2004-12-08 16:56 ` Stefan Monnier
2004-12-08 18:59 ` Zack Weinberg
2004-12-08 19:27 ` Stefan Monnier
2004-12-08 19:45 ` Zack Weinberg
2004-12-08 19:56 ` Stefan Monnier
2004-12-08 20:14 ` Nick Roberts
2004-12-08 22:47 ` Zack Weinberg
2004-12-08 23:40 ` Stefan Monnier
2004-12-09 1:20 ` Zack Weinberg
2004-12-09 2:11 ` Stefan Monnier
2004-12-09 2:33 ` Zack Weinberg
2004-12-09 2:46 ` Miles Bader
2004-12-09 3:08 ` Zack Weinberg
2004-12-09 3:28 ` Miles Bader
2004-12-09 3:48 ` Zack Weinberg
2004-12-09 4:04 ` Miles Bader
2004-12-09 4:41 ` Zack Weinberg
2004-12-09 4:52 ` Stefan Monnier
2004-12-09 5:33 ` Zack Weinberg [this message]
2004-12-09 5:39 ` Miles Bader
2004-12-09 6:49 ` Zack Weinberg
2004-12-09 15:22 ` Thien-Thi Nguyen
2004-12-10 5:50 ` Richard Stallman
2004-12-09 9:22 ` David Kastrup
2004-12-09 4:54 ` Miles Bader
2004-12-09 9:20 ` David Kastrup
2004-12-09 4:35 ` Stefan Monnier
2004-12-09 4:55 ` Zack Weinberg
2004-12-09 5:13 ` Stefan Monnier
2004-12-09 9:10 ` David Kastrup
2004-12-08 19:33 ` Paul Pogonyshev
2004-12-09 10:34 ` Andreas Schwab
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://www.gnu.org/software/emacs/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=878y88ox1k.fsf@codesourcery.com \
--to=zack@codesourcery.com \
--cc=emacs-devel@gnu.org \
--cc=miles@gnu.org \
--cc=snogglethorpe@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.savannah.gnu.org/cgit/emacs.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).