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| From | Stephen Sprunk <stephen@sprunk.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Why don't C comments nest? |
| Date | 2011-11-12 16:37 -0600 |
| Organization | A noiseless patient Spider |
| Message-ID | <j9msft$fkr$1@dont-email.me> (permalink) |
| References | (3 earlier) <lnobwi7421.fsf@nuthaus.mib.org> <4EBD936D.7040709@verizon.net> <lnk47672ah.fsf@nuthaus.mib.org> <j9lvd7$mn0$2@dont-email.me> <j9m0r9$127$1@dont-email.me> |
On 12-Nov-11 08:44, Eric Sosman wrote: > On 11/12/2011 9:21 AM, Stephen Sprunk wrote: >> On 11-Nov-11 15:54, Keith Thompson wrote: >>> C99 changed the syntax to permit a trailing comma in an enum >>> declaration. It would have made sense to permit a trailling >>> comma for *any* comma-separated list. (Probably not for the comma >>> operator, though.) >> >> Why not? If ";" is a valid statement, then why shouldn't ",;" be valid? > > Do you think `*;' should be valid? > > (If so, how many operands have been omitted? ;-) Amusing, but sort of misses the point since it hinges on _how_ "," is defined rather than defending _why_ it is so defined. Absent side effects, "x,y;" is equivalent to "y;". The expression "" cannot have side effects, so ",y;" should also be equivalent to "y;" and therefore be valid. Absent side effects, ",y;" is equivalent to ";". The expression "" cannot have side effects, so ",;" should also be equivalent to ";" and therefore valid. Absent side effects, "x,;" is equivalent to "x;". The expression "" cannot have side effects, so "x,;" should also be equivalent to ";" and therefore valid. The problem is that both operands must be evaluated by the operator before it can discard the results, and the current language definition does not define how to evaluate a null expression. However, what if it did? This is similar to not allowing objects of type void; such an object is obviously meaningless, but there are certain corner cases where uniformity matters more than meaning. S -- Stephen Sprunk "God does not play dice." --Albert Einstein CCIE #3723 "God is an inveterate gambler, and He throws the K5SSS dice at every possible opportunity." --Stephen Hawking
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Why don't C comments nest? Aron Packer <atp1@rightthing.invalid> - 2011-11-11 19:21 +0000
Re: Why don't C comments nest? James Kuyper <jameskuyper@verizon.net> - 2011-11-11 14:31 -0500
Re: Why don't C comments nest? Noob <root@127.0.0.1> - 2011-11-17 11:21 +0100
Re: Why don't C comments nest? Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-11-18 15:55 +0200
Re: Why don't C comments nest? nroberts <roberts.noah@gmail.com> - 2011-11-11 11:25 -0800
Re: Why don't C comments nest? Kaz Kylheku <kaz@kylheku.com> - 2011-11-11 20:11 +0000
Re: Why don't C comments nest? "BartC" <bc@freeuk.com> - 2011-11-11 20:28 +0000
Re: Why don't C comments nest? Keith Thompson <kst-u@mib.org> - 2011-11-11 13:16 -0800
Re: Why don't C comments nest? James Kuyper <jameskuyper@verizon.net> - 2011-11-11 16:28 -0500
Re: Why don't C comments nest? Keith Thompson <kst-u@mib.org> - 2011-11-11 13:54 -0800
Re: Why don't C comments nest? Willem <willem@toad.stack.nl> - 2011-11-12 12:07 +0000
Re: Why don't C comments nest? Keith Thompson <kst-u@mib.org> - 2011-11-12 13:11 -0800
Re: Why don't C comments nest? Willem <willem@toad.stack.nl> - 2011-11-12 22:29 +0000
Re: Why don't C comments nest? Keith Thompson <kst-u@mib.org> - 2011-11-12 16:36 -0800
Re: Why don't C comments nest? Willem <willem@toad.stack.nl> - 2011-11-13 10:30 +0000
Re: Why don't C comments nest? James Kuyper <jameskuyper@verizon.net> - 2011-11-13 06:31 -0500
Re: Why don't C comments nest? Willem <willem@toad.stack.nl> - 2011-11-13 16:57 +0000
Re: Why don't C comments nest? Stephen Sprunk <stephen@sprunk.org> - 2011-11-12 08:21 -0600
Re: Why don't C comments nest? Lauri Alanko <la@iki.fi> - 2011-11-12 14:29 +0000
Re: Why don't C comments nest? Acid Washed China Blue Jeans <chine.bleu@yahoo.com> - 2011-11-12 06:57 -0800
Re: Why don't C comments nest? Kaz Kylheku <kaz@kylheku.com> - 2011-11-12 17:51 +0000
Re: Why don't C comments nest? Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-12 09:44 -0500
Re: Why don't C comments nest? Stephen Sprunk <stephen@sprunk.org> - 2011-11-12 16:37 -0600
Re: Why don't C comments nest? Kenneth Brody <kenbrody@spamcop.net> - 2011-11-15 14:22 -0500
Re: Why don't C comments nest? Ian Collins <ian-news@hotmail.com> - 2011-11-16 08:41 +1300
Re: Why don't C comments nest? James Kuyper <jameskuyper@verizon.net> - 2011-11-15 14:48 -0500
Re: Why don't C comments nest? Ian Collins <ian-news@hotmail.com> - 2011-11-16 09:03 +1300
Re: Why don't C comments nest? "BartC" <bc@freeuk.com> - 2011-11-15 20:37 +0000
Re: Why don't C comments nest? Ian Collins <ian-news@hotmail.com> - 2011-11-16 10:06 +1300
Re: Why don't C comments nest? Keith Thompson <kst-u@mib.org> - 2011-11-15 14:31 -0800
Re: Why don't C comments nest? "BartC" <bc@freeuk.com> - 2011-11-15 22:41 +0000
Re: Why don't C comments nest? Kaz Kylheku <kaz@kylheku.com> - 2011-11-15 23:06 +0000
Re: Why don't C comments nest? "BartC" <bc@freeuk.com> - 2011-11-15 23:58 +0000
Re: Why don't C comments nest? Kaz Kylheku <kaz@kylheku.com> - 2011-11-16 01:58 +0000
Re: Why don't C comments nest? Willem <willem@toad.stack.nl> - 2011-11-15 22:40 +0000
Re: Why don't C comments nest? Ian Collins <ian-news@hotmail.com> - 2011-11-16 11:48 +1300
Re: Why don't C comments nest? Kaz Kylheku <kaz@kylheku.com> - 2011-11-15 23:13 +0000
Re: Why don't C comments nest? Kenneth Brody <kenbrody@spamcop.net> - 2011-11-16 12:57 -0500
Re: Why don't C comments nest? Ian Collins <ian-news@hotmail.com> - 2011-11-17 07:42 +1300
Re: Why don't C comments nest? John Gordon <gordon@panix.com> - 2011-11-16 18:57 +0000
Re: Why don't C comments nest? Ian Collins <ian-news@hotmail.com> - 2011-11-17 08:48 +1300
Re: Why don't C comments nest? Keith Thompson <kst-u@mib.org> - 2011-11-16 11:50 -0800
Re: Why don't C comments nest? Ian Collins <ian-news@hotmail.com> - 2011-11-17 09:00 +1300
Re: Why don't C comments nest? Kaz Kylheku <kaz@kylheku.com> - 2011-11-16 20:20 +0000
Re: Why don't C comments nest? blp@cs.stanford.edu (Ben Pfaff) - 2011-11-16 11:57 -0800
Re: Why don't C comments nest? Ian Collins <ian-news@hotmail.com> - 2011-11-17 09:47 +1300
Re: Why don't C comments nest? Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-11-18 15:49 +0200
Re: Why don't C comments nest? James Kuyper <jameskuyper@verizon.net> - 2011-11-18 10:15 -0500
Re: Why don't C comments nest? Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-11-18 17:57 +0200
Re: Why don't C comments nest? "BartC" <bc@freeuk.com> - 2011-11-11 22:14 +0000
Re: Why don't C comments nest? blp@cs.stanford.edu (Ben Pfaff) - 2011-11-11 14:35 -0800
Re: Why don't C comments nest? "BartC" <bc@freeuk.com> - 2011-11-12 00:10 +0000
Re: Why don't C comments nest? Keith Thompson <kst-u@mib.org> - 2011-11-11 15:14 -0800
Re: Why don't C comments nest? "BartC" <bc@freeuk.com> - 2011-11-12 00:37 +0000
Re: Why don't C comments nest? Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-11 20:21 -0500
Re: Why don't C comments nest? "BartC" <bc@freeuk.com> - 2011-11-12 11:10 +0000
Re: Why don't C comments nest? Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-12 08:11 -0500
Re: Why don't C comments nest? "BartC" <bc@freeuk.com> - 2011-11-12 13:57 +0000
Re: Why don't C comments nest? Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-12 09:34 -0500
Re: Why don't C comments nest? "BartC" <bc@freeuk.com> - 2011-11-12 18:17 +0000
Re: Why don't C comments nest? Robert Wessel <robertwessel2@yahoo.com> - 2011-11-12 14:09 -0600
Re: Why don't C comments nest? "BartC" <bc@freeuk.com> - 2011-11-12 20:49 +0000
Re: Why don't C comments nest? Keith Thompson <kst-u@mib.org> - 2011-11-12 13:42 -0800
Re: Why don't C comments nest? "BartC" <bc@freeuk.com> - 2011-11-12 21:53 +0000
Re: Why don't C comments nest? Kaz Kylheku <kaz@kylheku.com> - 2011-11-12 21:44 +0000
Re: Why don't C comments nest? "BartC" <bc@freeuk.com> - 2011-11-12 22:12 +0000
Re: Why don't C comments nest? Ian Collins <ian-news@hotmail.com> - 2011-11-13 11:22 +1300
Re: Why don't C comments nest? Keith Thompson <kst-u@mib.org> - 2011-11-12 16:32 -0800
Re: Why don't C comments nest? Keith Thompson <kst-u@mib.org> - 2011-11-12 13:09 -0800
Re: Why don't C comments nest? "BartC" <bc@freeuk.com> - 2011-11-12 21:46 +0000
Re: Why don't C comments nest? Seebs <usenet-nospam@seebs.net> - 2011-11-12 21:40 +0000
Re: Why don't C comments nest? Ian Collins <ian-news@hotmail.com> - 2011-11-12 11:20 +1300
Re: Why don't C comments nest? Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-11-12 00:40 +0200
Re: Why don't C comments nest? Kaz Kylheku <kaz@kylheku.com> - 2011-11-12 04:29 +0000
Re: Why don't C comments nest? "BartC" <bc@freeuk.com> - 2011-11-12 10:54 +0000
Re: Why don't C comments nest? Ian Collins <ian-news@hotmail.com> - 2011-11-13 09:11 +1300
Re: Why don't C comments nest? "BartC" <bc@freeuk.com> - 2011-11-12 20:52 +0000
Re: Why don't C comments nest? Ian Collins <ian-news@hotmail.com> - 2011-11-13 10:22 +1300
Re: Why don't C comments nest? Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-11-13 23:55 +0200
Re: Why don't C comments nest? Acid Washed China Blue Jeans <chine.bleu@yahoo.com> - 2011-11-12 07:02 -0800
Re: Why don't C comments nest? Keith Thompson <kst-u@mib.org> - 2011-11-12 13:13 -0800
Re: Why don't C comments nest? Acid Washed China Blue Jeans <chine.bleu@yahoo.com> - 2011-11-12 13:48 -0800
Re: Why don't C comments nest? Acid Washed China Blue Jeans <chine.bleu@yahoo.com> - 2011-11-11 16:51 -0800
Re: Why don't C comments nest? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2011-11-12 22:55 +0000
Re: Why don't C comments nest? Kenneth Brody <kenbrody@spamcop.net> - 2011-11-15 14:17 -0500
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