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Groups > comp.lang.c > #65561

Re: A Note on Readability

From James Kuyper <jameskuyper@verizon.net>
Newsgroups comp.lang.c
Subject Re: A Note on Readability
Date 2015-07-14 12:25 -0400
Organization A noiseless patient Spider
Message-ID <mo3d2d$128$1@dont-email.me> (permalink)
References (16 earlier) <55A3E9A3.7030602@verizon.net> <e4f73fe3-8173-4570-92c0-b4b6ca351e57@googlegroups.com> <55A406BC.1010203@verizon.net> <lnzj2zlvc9.fsf@kst-u.example.com> <b861aa1d-0fb8-4fd3-a695-c98f3c56a8b0@googlegroups.com>

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On 07/14/2015 11:45 AM, David Kleinecke wrote:
> On Monday, July 13, 2015 at 12:18:56 PM UTC-7, Keith Thompson wrote:
>> James Kuyper <jameskuyper@verizon.net> writes:
...
>>> Therefore, it must be parsed as the integer constant 3 followed by the
>>> identifier "until".
>>
>> Hmm?  As you just wrote, there's no splitting.  The preprocessor number
>> 3until is converted to a single token.  Since 3until is not a
>> syntactically valid token, it's a syntax error.  It's not equivalent to
>> the token 3 followed by the token until.
> 
> I dunno. 6.1.8 says that a pp-number can be, amomg other things, 
> a pp-number followed by a nondigit. I don't think nondigit is
> defined anywhere so I just assume it means letter. ...

In the current standard (sorry, I can't give you a C90 reference),
pp-number actually references identifier-nondigit, which in turn refers
to nondigit. Both identifier-nondigit and nondigit are defined in 6.4.2.1p1.

nondigit is almost what you're suggesting, but it also include
underscores. identifier-nondigit also allows universal-character-name,
(a Unicode-related addition to C99), and other implementation-defined
characters. The intent was for implementations to allow, at least as a
option, writing identifiers using characters native to languages that
can't be written using only the C basic character set.

> ... That makes 3until
> a legitimate pp-number. ...

Yes, that was a mistake on my part.

> ... Still one token though but no error message.  

It qualifies as a preprocessing-token, but it doesn't qualify as a token
- it does not parse correctly for any of the token types listed in
6.4p1. As a result, it is a constraint violation (6.4p2) for which a
diagnostic message is required.
-- 
James Kuyper

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Thread

A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-06 18:54 -0700
  A Note on Readability asetofsymbols@gmail.com - 2015-05-06 23:08 -0700
    Re: A Note on Readability Richard Heathfield <rjh@cpax.org.uk> - 2015-05-07 07:34 +0100
      Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-07 12:22 -0700
        Re: A Note on Readability raltbos@xs4all.nl (Richard Bos) - 2015-05-17 10:50 +0000
          Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-17 09:40 -0700
            Re: A Note on Readability Richard Heathfield <rjh@cpax.org.uk> - 2015-05-17 18:06 +0100
              Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-18 10:38 -0700
                Re: A Note on Readability James Kuyper <jameskuyper@verizon.net> - 2015-05-18 14:07 -0400
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-19 10:07 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-19 11:23 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-20 08:41 -0700
                Re: A Note on Readability asetofsymbols@gmail.com - 2015-05-20 09:03 -0700
                Re: A Note on Readability Les Cargill <lcargill99@comcast.com> - 2015-05-20 12:09 -0500
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-21 09:08 -0700
                Re: A Note on Readability Richard Heathfield <rjh@cpax.org.uk> - 2015-05-20 17:15 +0100
                Re: A Note on Readability Les Cargill <lcargill99@comcast.com> - 2015-05-20 12:10 -0500
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-21 08:58 -0700
                Re: A Note on Readability glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-05-21 17:33 +0000
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-22 09:47 -0700
                Re: A Note on Readability Les Cargill <lcargill99@comcast.com> - 2015-05-20 12:08 -0500
                Re: A Note on Readability James Kuyper <jameskuyper@verizon.net> - 2015-05-20 13:43 -0400
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-20 10:59 -0700
                Re: A Note on Readability Les Cargill <lcargill99@comcast.com> - 2015-05-20 18:05 -0500
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-20 17:36 -0700
                Re: A Note on Readability Les Cargill <lcargill99@comcast.com> - 2015-05-20 22:12 -0500
                Re: A Note on Readability Philip Lantz <prl@canterey.us> - 2015-05-20 20:34 -0700
                Re: A Note on Readability glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-05-21 04:39 +0000
                Re: A Note on Readability Philip Lantz <prl@canterey.us> - 2015-05-21 17:41 -0700
                Re: A Note on Readability gwowen <gwowen@gmail.com> - 2015-05-21 01:14 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-21 09:26 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-21 10:33 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-22 09:42 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-22 11:53 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-23 10:01 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-23 14:53 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-24 09:18 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-24 13:13 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-25 09:38 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-25 12:40 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-26 10:56 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-26 12:35 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-27 10:08 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-27 11:07 -0700
                Re: A Note on Readability Robert Wessel <robertwessel2@yahoo.com> - 2015-05-27 20:17 -0500
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-25 09:56 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-25 13:05 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-26 09:58 -0700
                Re: A Note on Readability Richard Heathfield <rjh@cpax.org.uk> - 2015-05-26 18:16 +0100
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-26 10:55 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-26 12:11 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-26 12:01 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-27 09:58 -0700
                Re: A Note on Readability Richard Heathfield <rjh@cpax.org.uk> - 2015-05-27 18:11 +0100
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-28 12:11 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-28 12:55 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-29 10:08 -0700
                Re: A Note on Readability Richard Heathfield <rjh@cpax.org.uk> - 2015-06-01 18:54 +0100
                Re: A Note on Readability Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-10 11:29 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-07-11 09:06 -0700
                Re: A Note on Readability Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-11 13:42 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-07-12 09:20 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-07-12 11:24 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-07-13 08:48 -0700
                Re: A Note on Readability James Kuyper <jameskuyper@verizon.net> - 2015-07-13 12:38 -0400
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-07-13 10:34 -0700
                Re: A Note on Readability James Kuyper <jameskuyper@verizon.net> - 2015-07-13 14:43 -0400
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-07-13 12:18 -0700
                Re: A Note on Readability James Kuyper <jameskuyper@verizon.net> - 2015-07-13 15:27 -0400
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-07-14 08:45 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-07-14 09:05 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-07-14 09:41 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-07-14 10:26 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-07-15 19:59 -0700
                Re: A Note on Readability James Kuyper <jameskuyper@verizon.net> - 2015-07-14 12:25 -0400
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-07-13 13:46 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-07-14 08:33 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-07-13 11:17 -0700
                Re: A Note on Readability Richard Damon <Richard@Damon-Family.org> - 2015-07-13 21:06 -0400
                Re: A Note on Readability James Kuyper <jameskuyper@verizon.net> - 2015-07-13 22:38 -0400
                Re: A Note on Readability Richard Damon <Richard@Damon-Family.org> - 2015-07-15 08:19 -0400
                Re: A Note on Readability Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-20 09:10 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-07-13 11:00 -0700
                Re: A Note on Readability Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-15 08:11 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-27 10:57 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-24 09:51 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-24 13:36 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-25 10:00 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-25 13:05 -0700
                Re: A Note on Readability Philip Lantz <prl@canterey.us> - 2015-05-24 16:43 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-24 09:57 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-24 13:37 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-25 10:14 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-25 13:11 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-26 10:26 -0700
                Re: A Note on Readability Richard Heathfield <rjh@cpax.org.uk> - 2015-05-26 18:38 +0100
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-26 12:24 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-27 10:06 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-27 11:05 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-26 10:38 -0700
                Re: A Note on Readability Tim Rentsch <txr@alumni.caltech.edu> - 2015-05-24 07:01 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-24 09:58 -0700
                Re: A Note on Readability Philip Lantz <prl@canterey.us> - 2015-05-25 00:45 -0700
                Re: A Note on Readability Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-10 11:09 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-21 09:04 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-21 10:36 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-22 09:56 -0700
                Re: A Note on Readability Robert Wessel <robertwessel2@yahoo.com> - 2015-05-22 12:16 -0500
                Re: A Note on Readability James Kuyper <jameskuyper@verizon.net> - 2015-05-22 14:14 -0400
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-23 09:49 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-22 11:55 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-22 11:58 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-20 10:26 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-18 11:08 -0700
                Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-19 10:09 -0700
                Re: A Note on Readability Richard Heathfield <rjh@cpax.org.uk> - 2015-05-18 20:40 +0100
            Re: A Note on Readability James Kuyper <jameskuyper@verizon.net> - 2015-05-17 14:34 -0400
              Re: A Note on Readability David Kleinecke <dkleinecke@gmail.com> - 2015-05-18 10:40 -0700
                Re: A Note on Readability Keith Thompson <kst-u@mib.org> - 2015-05-18 11:18 -0700
                Re: A Note on Readability James Kuyper <jameskuyper@verizon.net> - 2015-05-18 14:33 -0400
                Re: A Note on Readability Richard Heathfield <rjh@cpax.org.uk> - 2015-05-18 20:44 +0100
                Re: A Note on Readability James Kuyper <jameskuyper@verizon.net> - 2015-05-18 16:07 -0400

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