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Groups > comp.lang.c > #100356
| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Octal |
| Date | 2016-12-27 12:44 -0800 |
| Organization | None to speak of |
| Message-ID | <lneg0t6r1f.fsf@kst-u.example.com> (permalink) |
| References | (7 earlier) <9cb7833a-8479-4e61-8398-690783c4d975@googlegroups.com> <lnzijh6zrf.fsf@kst-u.example.com> <20280aee-5f78-47fa-ae22-c7bc852e3efb@googlegroups.com> <lnvau56sxg.fsf@kst-u.example.com> <f1ba350a-71c0-44cf-a57f-aace35f6f2f2@googlegroups.com> |
supercat@casperkitty.com writes:
> On Tuesday, December 27, 2016 at 2:02:18 PM UTC-6, Keith Thompson wrote:
>> supercat writes:
>> The fact that 0x123F+3 is allowed (meaning 0x123F + 3) and 0x123E+5
>> is not (because it's a single preprocessing number) is an odd little
>> glitch in the language. To the extent that it's a problem, it can
>> be neatly avoided with judicious use of spaces. It absolutely is
>> not, in my opinion, worth "fixing". Most programmers will never run
>> into it. Have you?
>
> As a matter of fact, a coworker of mine did run into it a little while ago
> when trying to tweak some code which made heavy use of hex constants, some
> of which needed to be bumped up slightly. Rather than editing the constants
> directly, he appended "+1", "+2", etc. I was able to help him with the
> syntax error that resulted when one of the constants happened to end with
> an E, but he didn't think he would have been able to figure out what was
> going on if I hadn't explained it.
Interesting.
> As for whether adding spaces improves legibility, that depends upon what else
> is on the lines in question. If one has a table of values that all need to
> be one larger than specified, appending +1 to every value will make all the
> entries two characters longer, but if entries had been separated by a space
> as well as a comma, the increase could be limited to one character. If one
> character will fit the editor/printer line width without wrapping or (for
> the editor only) scrolling, but two won't, having to add an extra space may
> make the table harder to inspect.
Ok, but I'm still not convinced it's worth changing the language
definition so you can avoid a little line wrapping.
You've shown one case of someone running into the issue. In that one
case, did adding spaces actually cause line width problems, or is that
just a theoretical issue? (If so, prepending "1+" rather than appending
"+1" would have been a workaround. Taking the time to modify the
constants, perhaps using a script, might have been even better.)
> A simple way to address the issue would be to say that compilers may at
> their option process 0x1E+1 as three tokens 0x1E + 1, or may issue a
> diagnostic. There are already many situations where some compilers will
> silently accept code for which others would issue a diagnostic (e.g.
>
> int q[256u*256u];
256u*256u clearly doesn't require a diagnostic. Compilers are permitted
to warn about anything they like.
> so I don't see anything to be gained by insisting that one compiler's
> inability to handle a construct should justify compelling all compilers to
> regard it as a constraint violation.
(It's a syntax error, not a constraint violation.)
Ok, so let's say the standard is updated to say that a conforming
compiler may, but need not, treat 0x1E+1 as three tokens --
and if it does so it needn't warn about it. You happen to use
that construct in your code, without being aware of the issue.
Years later you port the code to another compiler that rejects it.
But hey, at least you were *temporarily* able to save two whole
columns in one line of your C source file.
--
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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Octal BartC <bc@freeuk.com> - 2016-12-27 14:08 +0000
Octal "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-12-27 06:19 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-27 14:58 +0000
Re: Octal "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-12-27 07:07 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-27 15:22 +0000
Re: Octal "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-12-27 07:37 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-27 16:24 +0000
Re: Octal "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-12-27 08:30 -0800
Re: Octal supercat@casperkitty.com - 2016-12-27 09:10 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 09:35 -0800
Re: Octal supercat@casperkitty.com - 2016-12-27 10:47 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 12:03 -0800
Re: Octal supercat@casperkitty.com - 2016-12-27 12:27 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 12:44 -0800
Re: Octal supercat@casperkitty.com - 2016-12-27 13:37 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 16:38 -0800
Re: Octal supercat@casperkitty.com - 2016-12-27 17:53 -0800
Re: Octal Robert Wessel <robertwessel2@yahoo.com> - 2016-12-27 20:26 -0600
Re: Octal supercat@casperkitty.com - 2016-12-27 18:48 -0800
Re: Octal Robert Wessel <robertwessel2@yahoo.com> - 2016-12-27 22:20 -0600
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 18:41 -0800
Re: Octal supercat@casperkitty.com - 2016-12-27 19:19 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-29 14:52 +1300
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 18:41 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2016-12-28 16:54 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-27 17:44 +0000
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 12:17 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-27 22:39 +0000
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-28 11:49 +1300
Re: Octal BartC <bc@freeuk.com> - 2016-12-27 23:09 +0000
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-28 12:32 +1300
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 00:51 +0000
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-28 14:00 +1300
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 01:13 +0000
Re: Octal Robert Wessel <robertwessel2@yahoo.com> - 2016-12-27 20:04 -0600
Re: Octal supercat@casperkitty.com - 2016-12-27 18:45 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2016-12-29 13:35 -0800
Re: Octal supercat@casperkitty.com - 2016-12-29 14:49 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-29 15:33 -0800
Re: Octal supercat@casperkitty.com - 2016-12-30 12:35 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-13 15:19 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2017-01-13 15:32 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2017-01-14 12:35 +1300
Re: Octal Keith Thompson <kst-u@mib.org> - 2017-01-13 15:51 -0800
Re: Octal supercat@casperkitty.com - 2017-01-13 18:25 -0800
Re: Octal Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-14 06:21 -0800
Re: Octal supercat@casperkitty.com - 2017-01-14 14:00 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-15 23:08 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-15 23:02 -0800
Re: Octal supercat@casperkitty.com - 2017-01-13 18:52 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-15 23:46 -0800
Re: Octal supercat@casperkitty.com - 2017-01-16 01:46 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-31 08:33 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 17:19 -0800
Re: Octal raltbos@xs4all.nl (Richard Bos) - 2016-12-28 09:39 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 11:02 +0000
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-28 12:13 +0100
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 11:41 +0000
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 09:31 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 17:39 +0000
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-28 22:05 +0100
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 12:01 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 20:05 +0000
Re: Octal asetofsymbols@gmail.com - 2016-12-28 11:20 -0800
Re: Octal Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-28 12:01 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 12:30 +0000
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-28 13:51 +0100
Re: Octal Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-28 16:26 +0000
Re: Octal supercat@casperkitty.com - 2016-12-28 08:40 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 09:41 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 18:04 +0000
Re: Octal Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-28 19:36 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 19:42 +0000
Re: Octal Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-29 00:34 +0000
Re: Octal supercat@casperkitty.com - 2016-12-28 11:04 -0800
Re: Octal raltbos@xs4all.nl (Richard Bos) - 2016-12-28 12:09 +0000
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 16:46 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 00:56 +0000
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 17:52 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 11:27 +0000
Re: Octal Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-28 12:09 +0000
Re: Octal supercat@casperkitty.com - 2016-12-28 08:17 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 17:02 +0000
Re: Octal Ike Naar <ike@iceland.freeshell.org> - 2016-12-28 17:25 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 17:45 +0000
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 10:21 -0800
Re: Octal supercat@casperkitty.com - 2016-12-28 09:27 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 10:23 -0800
Re: Octal supercat@casperkitty.com - 2016-12-28 11:18 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 10:19 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-29 15:54 +0000
Re: Octal Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-12-29 12:57 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-30 10:01 +1300
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-30 10:44 +0100
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-29 17:32 +0100
Re: Octal BartC <bc@freeuk.com> - 2016-12-29 17:03 +0000
Re: Octal Robert Wessel <robertwessel2@yahoo.com> - 2016-12-29 16:26 -0600
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-30 11:31 +1300
Re: Octal Robert Wessel <robertwessel2@yahoo.com> - 2016-12-29 16:58 -0600
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-30 11:59 +1300
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-30 09:00 +1300
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-30 10:21 +0100
Re: Octal asetofsymbols@gmail.com - 2016-12-30 01:29 -0800
Re: Octal asetofsymbols@gmail.com - 2016-12-30 01:29 -0800
Re: Octal asetofsymbols@gmail.com - 2016-12-30 01:36 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-29 11:52 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-29 17:10 +0000
Re: Octal supercat@casperkitty.com - 2016-12-29 05:52 -0800
Re: Octal Robert Wessel <robertwessel2@yahoo.com> - 2016-12-28 19:51 -0600
Re: Octal BartC <bc@freeuk.com> - 2016-12-29 21:09 +0000
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-30 10:15 +1300
Re: Octal Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-12-29 13:53 -0800
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-30 12:07 +0100
Re: Octal BartC <bc@freeuk.com> - 2016-12-30 13:04 +0000
Re: Octal Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-12-30 05:31 -0800
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-30 15:00 +0100
Re: Octal BartC <bc@freeuk.com> - 2016-12-30 15:55 +0000
Re: Octal David Brown <david.brown@hesbynett.no> - 2017-01-01 16:00 +0100
Re: Octal Ian Collins <ian-news@hotmail.com> - 2017-01-02 08:33 +1300
Re: Octal Ian Collins <ian-news@hotmail.com> - 2017-01-02 09:02 +1300
Re: Octal Ian Collins <ian-news@hotmail.com> - 2017-01-02 09:38 +1300
Re: Octal Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-01 13:59 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2017-01-01 14:24 -0800
Re: Octal supercat@casperkitty.com - 2017-01-01 15:51 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2017-01-02 13:09 +1300
Re: Octal supercat@casperkitty.com - 2017-01-01 16:50 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2017-01-02 14:24 +1300
Re: Octal David Brown <david.brown@hesbynett.no> - 2017-01-02 01:53 +0100
Re: Octal Ian Collins <ian-news@hotmail.com> - 2017-01-02 14:15 +1300
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-02 02:28 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-31 06:24 +1300
Re: Octal BartC <bc@freeuk.com> - 2016-12-30 17:53 +0000
Re: Octal luser droog <luser.droog@gmail.com> - 2016-12-30 10:01 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-31 09:57 +1300
Re: Octal supercat@casperkitty.com - 2016-12-30 13:50 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-31 11:09 +1300
Re: Octal supercat@casperkitty.com - 2016-12-30 14:46 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-31 12:28 +1300
Re: Octal supercat@casperkitty.com - 2016-12-30 16:01 -0800
Re: Octal Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-12-30 14:48 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-30 22:51 +0000
Re: Octal supercat@casperkitty.com - 2016-12-30 15:20 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-31 12:34 +1300
Re: Octal BartC <bc@freeuk.com> - 2016-12-30 23:40 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-30 22:12 +0000
Re: Octal raltbos@xs4all.nl (Richard Bos) - 2016-12-28 21:38 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-29 12:04 +0000
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-29 13:42 +0100
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-30 08:59 +1300
Re: Octal supercat@casperkitty.com - 2016-12-29 12:23 -0800
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-30 10:56 +0100
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 22:09 +0000
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-29 12:27 +0100
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 21:18 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 20:46 +0000
Re: Octal raltbos@xs4all.nl (Richard Bos) - 2016-12-28 20:55 +0000
Re: Octal Robert Wessel <robertwessel2@yahoo.com> - 2016-12-28 14:54 -0600
Re: Octal BartC <bc@freeuk.com> - 2016-12-29 15:44 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 19:39 +0000
Re: Octal Robert Wessel <robertwessel2@yahoo.com> - 2016-12-28 15:04 -0600
Re: Octal raltbos@xs4all.nl (Richard Bos) - 2016-12-28 19:52 +0000
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-29 09:36 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-29 18:02 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-30 16:17 +0000
Re: Octal David Brown <david.brown@hesbynett.no> - 2017-01-01 16:09 +0100
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 20:02 +0000
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 12:32 -0800
Re: Octal Richard Heathfield <rjh@cpax.org.uk> - 2016-12-29 13:45 +0000
Re: Octal Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-28 17:16 +0000
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 10:04 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-02 02:26 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2017-01-02 12:35 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-12 23:22 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2017-01-13 10:04 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-14 00:45 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 09:59 -0800
Re: Octal "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-12-27 09:45 -0800
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-27 17:14 +0100
Re: Octal "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-12-27 08:23 -0800
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-28 10:37 +0100
Re: Octal "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-12-28 03:07 -0800
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-28 12:25 +0100
Re: Octal Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-28 11:58 +0000
Re: Octal "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-12-28 04:35 -0800
Re: Octal Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-28 17:31 +0000
Re: Octal "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-12-28 09:38 -0800
Re: Octal Robert Wessel <robertwessel2@yahoo.com> - 2016-12-28 15:12 -0600
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 12:01 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 09:20 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 13:39 -0800
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-29 12:29 +0100
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-28 22:20 +0100
Re: Octal Noob <root@127.0.0.1> - 2016-12-28 13:02 +0100
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-28 13:30 +0100
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 13:25 +0000
Re: Octal Manfred <noname@invalid.add> - 2016-12-27 15:19 +0100
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 08:37 -0800
Re: Octal Manfred <noname@invalid.add> - 2016-12-27 18:43 +0100
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 12:07 -0800
Re: Octal Manfred <noname@invalid.add> - 2016-12-27 18:21 +0100
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-27 15:28 +0100
Re: Octal BGB <cr88192@hotmail.com> - 2016-12-27 11:42 -0600
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