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| From | Kaz Kylheku <kaz@kylheku.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Why don't C comments nest? |
| Date | 2011-11-16 01:58 +0000 |
| Organization | A noiseless patient Spider |
| Message-ID | <20111115174424.888@kylheku.com> (permalink) |
| References | (6 earlier) <H_KdnY0vhu-BIV_TnZ2dnUVZ_gmdnZ2d@bestweb.net> <9iftjkFi5oU1@mid.individual.net> <j9ujef$qfi$1@dont-email.me> <20111115150328.947@kylheku.com> <j9uucs$4ir$1@dont-email.me> |
On 2011-11-15, BartC <bc@freeuk.com> wrote:
> "Kaz Kylheku" <kaz@kylheku.com> wrote in message
> news:20111115150328.947@kylheku.com...
>> On 2011-11-15, BartC <bc@freeuk.com> wrote:
>
>>> I just happen to think that #if 0 is a ugly way of doing this (with a few
>>> problems of it's own), while nested comments is an elegant way.
>>
>> I showed several times how a simple macro can do it this way within
>> one line:
>>
>> #define IGN(...) /* C99 variadic */
>>
>> some_function(10, 20, IGN(30, ) );
>>
>> Nests and everything:
>>
>> IGN( IGN ( ... ) IGN ( IGN ( ... ) ) )
>
> I didn't believe it, but it seems to work...
Why didn't you believe it? I often test stuff before posting! :)
>> balanced parentheses. I could live with that.
>
> I called mine COM() (why IGN?), and it means comments can be written like
> this:
Because, sigh, it's not commenting! It's for ignoring program tokens.
IGN comes from the Common Lisp habit: #+IGN expr causes expr to be
ignored, assuming the symbol :IGN is not in the platform *features* list.
I've never seen Lisp's #+ or #- used for commenting; that is ridiculous.
(Lisp people: don't shoot me, I know this kludge is frowned upon by some,
and I don't use it myself, but rather #+(and) expr.)
> But, both have similar problems in that either ( and ), or /* and */, must
> be balanced, so from that point of view, what would be the difference?
> Of course, nested COM() (or whatever it might be called) exists now, and
> nested /**/ doesn't. But the argument against nested /**/ *was* that stray
> /* or */ sequences would trip it up, in the same way that extra ( or ) might
> cause a problem in the macro.
The differences is that the stuff inside IGN(...) is preprocessor tokens, not
an arbitrary comment. It syntactically has to be a valid macro call! So it is
not messed up by the following:
IGN( char lparen = '('; )
On the other and it is messed up by this:
if (!x)
foo(); IGN(Don't foo if x is true!)
Do you still want to call it COM?
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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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