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| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: // comments and \ |
| Date | 2015-12-01 12:33 -0800 |
| Organization | None to speak of |
| Message-ID | <lntwo1ucwm.fsf@kst-u.example.com> (permalink) |
| References | (5 earlier) <63922dcf-c5cb-4aae-a271-d1fe0b450603@googlegroups.com> <87y4deccp1.fsf@bsb.me.uk> <463ed1ae-80d5-4718-8cb9-6e0d95e3a005@googlegroups.com> <ln37vmugvl.fsf@kst-u.example.com> <eb422b03-1a96-47c3-9ccc-4e3fe2b52cd5@googlegroups.com> |
supercat@casperkitty.com writes:
> On Tuesday, December 1, 2015 at 1:08:22 PM UTC-6, Keith Thompson wrote:
>> To be clear, you're suggesting handling // comments before phase 1.
>>
>> Phase 1 is:
>> Physical source file multibyte characters are mapped, in an
>> implementation-defined manner, to the source character set
>> (introducing new-line characters for end-of-line indicators)
>> if necessary. Trigraph sequences are replaced by corresponding
>> single-character internal representations.
>
> Yup. Some compilers make it difficult to insert translation steps between
> other compilation phases, so allowing "//" processing to precede phase 1
> would have allowed files containing such comments to be supported on such
> systems. That wouldn't imply that all systems would have to add an extra
> step--merely that the rules should be consistent with such an approach.
>
> It doesn't take much of a state machine to recognize string or character
> literals or /* */ comments. While I like your idea of replacing the
> backslash-newline with a special marker character, I'd add an additional
> rule which would say that use of a backslash-newline in contexts where
> whitespace would be significant should be deprecated.
Existing compilers don't even agree on the interpretation of the
current rules. You propose adding a whole new layer of complexity.
You would separate the procesing of "//" and "/*...*/" comments
into two different translation phases, which I find badly
counterintuitive. Among other problems, it would introduce a
whole new set of opportunities for misinterpretation of the rules.
I don't know what odd corner cases your proposal would introduce.
And your proposal breaks, or at least seriously bends, the
translation phase model, requiring certain lexical elements to be
recognized in two or more different phases.
I don't see much benefit from your proposal, except *maybe* that
some obscure constructs (that probably shouldn't appear in source
code in the first place) might be rejected.
The problem could be mostly solved by compilers issuing warnings
for certain corner cases. Clang already warns about "backslash
and newline separated by space"; other compilers could do so as well.
I proposed a different solution, changing the behavior of phases
2 and 3. I don't actually think that's necessarily a good idea;
it's just a cleaner way of handling the corner case.
--
Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
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// comments and \ BartC <bc@freeuk.com> - 2015-12-01 12:52 +0000
Re: // comments and \ me <self@example.org> - 2015-12-01 13:08 +0000
Re: // comments and \ Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-12-01 08:20 -0500
Re: // comments and \ me <self@example.org> - 2015-12-01 13:36 +0000
Re: // comments and \ Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-12-01 09:03 -0500
Re: // comments and \ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-12-01 14:14 +0000
Re: // comments and \ supercat@casperkitty.com - 2015-12-01 07:40 -0800
Re: // comments and \ Keith Thompson <kst-u@mib.org> - 2015-12-01 08:55 -0800
Re: // comments and \ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-12-01 17:15 +0000
Re: // comments and \ supercat@casperkitty.com - 2015-12-01 09:58 -0800
Re: // comments and \ Richard Heathfield <rjh@cpax.org.uk> - 2015-12-01 18:11 +0000
Re: // comments and \ supercat@casperkitty.com - 2015-12-01 10:18 -0800
Re: // comments and \ Richard Heathfield <rjh@cpax.org.uk> - 2015-12-01 18:20 +0000
Re: // comments and \ Keith Thompson <kst-u@mib.org> - 2015-12-01 11:07 -0800
Re: // comments and \ supercat@casperkitty.com - 2015-12-01 11:39 -0800
Re: // comments and \ Keith Thompson <kst-u@mib.org> - 2015-12-01 12:33 -0800
Re: // comments and \ glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-12-02 01:05 +0000
Re: // comments and \ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-12-01 19:30 +0000
Re: // comments and \ David Brown <david.brown@hesbynett.no> - 2015-12-01 20:59 +0100
Re: // comments and \ James Kuyper <jameskuyper@verizon.net> - 2015-12-01 15:22 -0500
Re: // comments and \ Richard Heathfield <rjh@cpax.org.uk> - 2015-12-01 20:37 +0000
Re: // comments and \ Robert Wessel <robertwessel2@yahoo.com> - 2015-12-01 14:56 -0600
Re: // comments and \ David Brown <david.brown@hesbynett.no> - 2015-12-01 22:11 +0100
Re: // comments and \ Philip Lantz <prl@canterey.us> - 2015-12-02 03:01 -0800
Re: // comments and \ glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-12-02 00:45 +0000
Re: // comments and \ Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2015-12-01 07:52 -0700
Re: // comments and \ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-12-01 15:19 +0000
Re: // comments and \ Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2015-12-01 08:29 -0700
Re: // comments and \ Richard Heathfield <rjh@cpax.org.uk> - 2015-12-01 15:35 +0000
Re: // comments and \ Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2015-12-01 09:21 -0700
Re: // comments and \ Richard Heathfield <rjh@cpax.org.uk> - 2015-12-01 16:41 +0000
Re: // comments and \ Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2015-12-01 10:15 -0700
Re: // comments and \ Richard Heathfield <rjh@cpax.org.uk> - 2015-12-01 17:24 +0000
Re: // comments and \ Richard Heathfield <rjh@cpax.org.uk> - 2015-12-01 17:43 +0000
Re: // comments and \ Philip Lantz <prl@canterey.us> - 2015-12-02 03:05 -0800
Re: // comments and \ Richard Heathfield <rjh@cpax.org.uk> - 2015-12-02 11:40 +0000
Re: // comments and \ Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-12-02 04:29 -0800
Re: // comments and \ BartC <bc@freeuk.com> - 2015-12-01 19:11 +0000
Re: // comments and \ Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-12-01 20:43 +0000
Re: // comments and \ BartC <bc@freeuk.com> - 2015-12-01 21:04 +0000
Re: // comments and \ Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-12-01 21:16 +0000
Re: // comments and \ Philip Lantz <prl@canterey.us> - 2015-12-02 03:12 -0800
Re: // comments and \ BartC <bc@freeuk.com> - 2015-12-02 11:52 +0000
Re: // comments and \ Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-12-02 04:40 -0800
Re: // comments and \ David Brown <david.brown@hesbynett.no> - 2015-12-02 13:55 +0100
Re: // comments and \ BartC <bc@freeuk.com> - 2015-12-02 13:56 +0000
Re: // comments and \ David Brown <david.brown@hesbynett.no> - 2015-12-02 15:24 +0100
Re: // comments and \ supercat@casperkitty.com - 2015-12-02 06:54 -0800
Re: // comments and \ David Brown <david.brown@hesbynett.no> - 2015-12-02 16:40 +0100
Re: // comments and \ Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-12-02 18:24 +0000
Re: // comments and \ Öö Tiib <ootiib@hot.ee> - 2015-12-02 20:27 -0800
Re: // comments and \ Keith Thompson <kst-u@mib.org> - 2015-12-02 23:22 -0800
Re: // comments and \ Öö Tiib <ootiib@hot.ee> - 2015-12-03 00:57 -0800
Re: // comments and \ Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-12-03 23:44 +0000
Re: // comments and \ Öö Tiib <ootiib@hot.ee> - 2015-12-03 21:17 -0800
Re: // comments and \ Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-12-05 00:43 +0000
Re: // comments and \ Les Cargill <lcargill99@comcast.com> - 2015-12-04 20:32 -0600
Re: // comments and \ Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-12-05 16:06 +0000
Re: // comments and \ Les Cargill <lcargill99@comcast.com> - 2015-12-05 13:10 -0600
Re: // comments and \ Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-12-06 10:18 +0000
Re: // comments and \ Les Cargill <lcargill99@comcast.com> - 2015-12-06 14:26 -0600
Re: // comments and \ David Brown <david.brown@hesbynett.no> - 2015-12-03 12:45 +0100
Re: // comments and \ raltbos@xs4all.nl (Richard Bos) - 2015-12-04 11:45 +0000
Re: // comments and \ Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-12-04 04:20 -0800
Re: // comments and \ David Brown <david.brown@hesbynett.no> - 2015-12-04 14:20 +0100
Re: // comments and \ James Kuyper <jameskuyper@verizon.net> - 2015-12-04 10:05 -0500
Re: // comments and \ David Brown <david.brown@hesbynett.no> - 2015-12-04 17:31 +0100
Re: // comments and \ Les Cargill <lcargill99@comcast.com> - 2015-12-04 17:24 -0600
Re: // comments and \ James Kuyper <jameskuyper@verizon.net> - 2015-12-04 18:50 -0500
Re: // comments and \ Les Cargill <lcargill99@comcast.com> - 2015-12-04 20:34 -0600
Re: // comments and \ raltbos@xs4all.nl (Richard Bos) - 2015-12-10 20:40 +0000
Re: // comments and \ Keith Thompson <kst-u@mib.org> - 2015-12-04 09:36 -0800
Re: // comments and \ Richard Damon <Richard@Damon-Family.org> - 2015-12-05 09:05 -0500
Re: // comments and \ Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-12-05 17:42 +0000
Re: // comments and \ David Brown <david.brown@hesbynett.no> - 2015-12-06 22:23 +0100
Re: // comments and \ Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-12-07 21:59 +0000
Re: // comments and \ Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-12-05 15:50 +0000
Re: // comments and \ David Brown <david.brown@hesbynett.no> - 2015-12-05 18:17 +0100
Re: // comments and \ Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-12-06 10:01 +0000
Re: // comments and \ Öö Tiib <ootiib@hot.ee> - 2015-12-06 03:05 -0800
Re: // comments and \ Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-12-06 04:07 -0800
Re: // comments and \ Öö Tiib <ootiib@hot.ee> - 2015-12-06 04:37 -0800
Re: // comments and \ Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-12-06 05:05 -0800
Re: // comments and \ Keith Thompson <kst-u@mib.org> - 2015-12-06 12:19 -0800
Re: // comments and \ Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-12-06 13:59 +0000
Re: // comments and \ Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-12-06 06:09 -0800
Re: // comments and \ Öö Tiib <ootiib@hot.ee> - 2015-12-06 07:30 -0800
Re: // comments and \ Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-12-06 18:55 +0000
Re: // comments and \ Keith Thompson <kst-u@mib.org> - 2015-12-06 12:23 -0800
Re: // comments and \ Keith Thompson <kst-u@mib.org> - 2015-12-06 12:22 -0800
Re: // comments and \ Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-12-06 21:06 +0000
Re: // comments and \ Les Cargill <lcargill99@comcast.com> - 2015-12-05 13:14 -0600
Re: // comments and \ Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-12-06 10:09 +0000
Re: // comments and \ mark.bluemel@gmail.com - 2015-12-03 06:15 -0800
Re: // comments and \ Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2015-12-02 08:28 -0700
Re: // comments and \ Keith Thompson <kst-u@mib.org> - 2015-12-02 09:01 -0800
Re: // comments and \ Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-12-02 21:52 +0000
Re: // comments and \ Keith Thompson <kst-u@mib.org> - 2015-12-02 16:55 -0800
Re: // comments and \ David Brown <david.brown@hesbynett.no> - 2015-12-03 13:11 +0100
Re: // comments and \ Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-12-03 23:21 +0000
Re: // comments and \ David Brown <david.brown@hesbynett.no> - 2015-12-04 11:22 +0100
Re: // comments and \ Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-12-05 01:12 +0000
Re: // comments and \ Les Cargill <lcargill99@comcast.com> - 2015-12-04 20:39 -0600
Re: // comments and \ raltbos@xs4all.nl (Richard Bos) - 2015-12-04 11:14 +0000
Re: // comments and \ Richard Heathfield <rjh@cpax.org.uk> - 2015-12-04 12:25 +0000
Re: // comments and \ David Brown <david.brown@hesbynett.no> - 2015-12-04 14:23 +0100
Re: // comments and \ Keith Thompson <kst-u@mib.org> - 2015-12-01 09:00 -0800
Re: // comments and \ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-12-01 19:46 +0000
Re: // comments and \ Richard Heathfield <rjh@cpax.org.uk> - 2015-12-01 20:36 +0000
Re: // comments and \ Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2015-12-01 20:37 -0700
Re: // comments and \ BartC <bc@freeuk.com> - 2015-12-01 14:26 +0000
Re: // comments and \ Richard Heathfield <rjh@cpax.org.uk> - 2015-12-01 14:32 +0000
Re: // comments and \ BartC <bc@freeuk.com> - 2015-12-01 14:52 +0000
Re: // comments and \ David Brown <david.brown@hesbynett.no> - 2015-12-01 16:15 +0100
Re: // comments and \ Richard Heathfield <rjh@cpax.org.uk> - 2015-12-01 15:28 +0000
Re: // comments and \ glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-12-02 01:26 +0000
Re: // comments and \ Keith Thompson <kst-u@mib.org> - 2015-12-01 09:12 -0800
Re: // comments and \ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-12-01 19:17 +0000
Re: // comments and \ Robert Wessel <robertwessel2@yahoo.com> - 2015-12-01 12:32 -0600
Re: // comments and \ Nobody <nobody@nowhere.invalid> - 2015-12-02 00:01 +0000
Re: // comments and \ supercat@casperkitty.com - 2015-12-02 07:08 -0800
Re: // comments and \ Nobody <nobody@nowhere.invalid> - 2015-12-02 21:05 +0000
Re: // comments and \ Keith Thompson <kst-u@mib.org> - 2015-12-02 14:22 -0800
Re: // comments and \ supercat@casperkitty.com - 2015-12-02 14:48 -0800
Re: // comments and \ glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-12-02 23:37 +0000
Re: // comments and \ supercat@casperkitty.com - 2015-12-02 17:10 -0800
Re: // comments and \ Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-12-02 19:24 -0800
Re: // comments and \ Richard Heathfield <rjh@cpax.org.uk> - 2015-12-03 04:10 +0000
Re: // comments and \ Philip Lantz <prl@canterey.us> - 2015-12-02 21:49 -0800
Re: // comments and \ Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2015-12-03 07:28 -0700
Re: // comments and \ supercat@casperkitty.com - 2015-12-03 09:12 -0800
Re: // comments and \ supercat@casperkitty.com - 2015-12-03 06:53 -0800
Re: // comments and \ supercat@casperkitty.com - 2015-12-03 15:41 -0800
Re: // comments and \ Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-12-03 15:56 -0800
Re: // comments and \ supercat@casperkitty.com - 2015-12-03 16:44 -0800
Re: // comments and \ Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-12-03 17:29 -0800
Re: // comments and \ supercat@casperkitty.com - 2015-12-03 19:10 -0800
Re: // comments and \ Philip Lantz <prl@canterey.us> - 2015-12-02 21:59 -0800
Re: // comments and \ Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2015-12-01 07:52 -0700
Re: // comments and \ Keith Thompson <kst-u@mib.org> - 2015-12-01 09:21 -0800
Re: // comments and \ Richard Heathfield <rjh@cpax.org.uk> - 2015-12-01 17:26 +0000
Re: // comments and \ Keith Thompson <kst-u@mib.org> - 2015-12-01 10:50 -0800
Re: // comments and \ Keith Thompson <kst-u@mib.org> - 2015-12-01 10:49 -0800
Re: // comments and \ Geoff <geoff@invalid.invalid> - 2015-12-01 11:34 -0800
Re: // comments and \ David Thompson <dave.thompson2@verizon.net> - 2015-12-22 06:44 -0500
Re: // comments and \ "Charles Richmond" <numerist@aquaporin4.com> - 2015-12-23 14:35 -0600
Re: // comments and \ Keith Thompson <kst-u@mib.org> - 2015-12-23 13:00 -0800
Re: // comments and \ James Kuyper <jameskuyper@verizon.net> - 2015-12-23 16:58 -0500
Re: // comments and \ Keith Thompson <kst-u@mib.org> - 2015-12-23 14:21 -0800
Re: // comments and \ James Kuyper <jameskuyper@verizon.net> - 2015-12-23 16:55 -0500
Re: // comments and \ Öö Tiib <ootiib@hot.ee> - 2015-12-01 12:24 -0800
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