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| From | Kaz Kylheku <kaz@kylheku.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Why don't C comments nest? |
| Date | 2011-11-12 04:29 +0000 |
| Organization | A noiseless patient Spider |
| Message-ID | <20111111201323.325@kylheku.com> (permalink) |
| References | <j9jsj2$7gi$1@speranza.aioe.org> <20111111115530.783@kylheku.com> <j9k0it$j5j$1@dont-email.me> |
On 2011-11-11, BartC <bc@freeuk.com> wrote:
> "Kaz Kylheku" <kaz@kylheku.com> wrote in message
>> This way, for instance, the following will not break:
>>
>> /* char *comment_end = "/*"; */
>
>> Here, "/*" is embedded in a string literal token and so loses
>> the comment-closing meaning.
>
> You mean "*/"? In which case you can't even write it whether you have nested
> comments or not:
That's my point. You can't write it without nested comments, but nested
comments don't fix anything.
>> Note that if you allow only tokens between /* and */, then it becomes
>> more difficult to write comments, which cannot be freeform text.
>>
>> The #if 0 directive solves the embedding problem, because material which
>> is
>
> Perhaps have #comment ... #end then
That's a useless syntactic sugar for #if 0; furthermore, it's badly
named since this feature is not for commenting. Your "comment" has
to be written in valid C preprocessor tokens.
Really, do you need to be able to invoke undefined behavior in comments? :)
> Suppose the code you want to comment out is the middle of a line, which is
> already using /*...*/ ?
There is this:
C89:
#define IGN(X)
IGN( foo() );
void bar(IGN( const ) int *ptr)
{
}
Now, an unparenthesized comma doesn't work, e,g. IGN(A, B).
C99 varidic macros to the rescue:
#define IGN(...)
struct x y = { 1, 2 IGN( , 3, 4 ) };
Or you could just edit the darn code. Remove the inner /* */ and add the outer
ones. There are few enough people working in C, and out of those few enough who
have this problem, that it's not some kind of wide-spread economic problem.
Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
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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