Groups > comp.lang.c > #142013

Re: [ On topic, amazingtly ]: labels and declarations

From	Keith Thompson <kst-u@mib.org>
Newsgroups	comp.lang.c
Subject	Re: [ On topic, amazingtly ]: labels and declarations
Date	2019-03-17 21:08 -0700
Organization	None to speak of
Message-ID	<ln36nkkeor.fsf@kst-u.example.com> (permalink)
References	(3 earlier) <lnbm29jdn2.fsf@kst-u.example.com> <q6ml86$6dj$1@dont-email.me> <ln7ecxjc2n.fsf@kst-u.example.com> <86bm29qaih.fsf@mailhub.linuxsc.com> <BKDjE.13578$N14.3528@fx17.iad>

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Richard Damon <Richard@Damon-Family.org> writes:
> On 3/17/19 8:41 PM, Tim Rentsch wrote:
>> Keith Thompson <kst-u@mib.org> writes:
>>>
>>> In Richard's example, if the scopes of the two `x`s extended beyond the
>>> if-else statement, it would be difficult to define the semantics or,
>>> more likely, the second declaration would be illegal for the same
>>> reason.  If the scopes were defined as they are in C++, they would be
>>> non-overlapping and unambiguous (and not useful, since nothing could
>>> refer to either `x`).
>> 
>> I think you (and also Richard Damon) are forgetting 6.8.4 p3
>> (already present in C99, though not in C90):
>> 
>>     A selection statement is a block whose scope is a strict
>>     subset of the scope of its enclosing block.  Each associated
>>     substatement is also a block whose scope is a strict subset
>>     of the scope of the selection statement.
>> 
> I will admit that I hadn't followed the standards into that detail an
> missed that they changed to make the statements implicit scopes.
>
> With that changed, I am not sure if there is any particular difficulty
> in changing the grammar so that declarations are fully a statement, and
> thus could have a label in front of it.
>
> The biggest issue that I can think of is this would likely move and
> renumber all the requirements on Declarations (basically 6.7) to be
> under Statements(6.8, which would then become 6.7 and 6.7 was moved),
> probably after jump statements (6.8.6 now, 6.7.6 with the above
> renumbering), so all 6.7.x numbers become 6.7.7.x, and 6.8.x becomes
> 6.7.x. and all the 6.x above 8 get renumbers a step lower.

In the 2011 C++ standard, section 6 is Statements, section 7 is
Declarations, and section 6.7 is Declaration statements.

Not all declarations are statements in C++, only those that appear
in a context that permits a statement.

I don't think that treating declarations as statements would require
any radical changes to the C standard, but I don't think it would
be worth doing.  I'm not aware of any significant problems that
it would solve.  (Having to add a semicolon after a label in some
contexts is not, in my opinion, a significant problem.)

(Just a reminder: Tim Rentsch is still in my killfile, so don't infer
anything if I don't respond to something he writes.)

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Will write code for food.
void Void(void) { Void(); } /* The recursive call of the void */

Thread

[ On topic, amazingtly ]: labels and declarations gazelle@shell.xmission.com (Kenny McCormack) - 2019-03-17 14:45 +0000
  Re: [ On topic, amazingtly ]: labels and declarations nobody@example.org (Scott) - 2019-03-17 17:25 +0000
    Re: [ On topic, amazingtly ]: labels and declarations fir is a sexy shemale <cdalten@gmail.com> - 2019-03-17 10:59 -0700
  Re: [ On topic, amazingtly ]: labels and declarations Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2019-03-17 14:16 -0400
    Re: [ On topic, amazingtly ]: labels and declarations Richard Damon <Richard@Damon-Family.org> - 2019-03-17 18:43 -0400
      Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-17 22:55 +0000
        Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-18 01:37 +0000
        Re: [ On topic, amazingtly ]: labels and declarations Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-17 19:46 -0700
          Re: [ On topic, amazingtly ]: labels and declarations David Brown <david.brown@hesbynett.no> - 2019-03-18 08:41 +0100
            Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-18 11:20 +0000
              Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 04:39 -0700
                Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-18 12:08 +0000
                Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 05:26 -0700
                labels and declarations and debugger breakpoints "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 05:40 -0700
                Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-18 17:25 +0000
                Re: [ On topic, amazingtly ]: labels and declarations gazelle@shell.xmission.com (Kenny McCormack) - 2019-03-18 19:11 +0000
                Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-19 01:36 +0000
                Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 12:31 -0700
                Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-18 19:57 +0000
                Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 13:09 -0700
                Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-18 21:09 +0000
                Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 16:03 -0700
                Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-18 23:49 +0000
                Re: [ On topic, amazingtly ]: labels and declarations fir is a sexy shemale <cdalten@gmail.com> - 2019-03-18 16:53 -0700
                Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 18:03 -0700
              Re: [ On topic, amazingtly ]: labels and declarations David Brown <david.brown@hesbynett.no> - 2019-03-18 13:16 +0100
                Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-18 12:30 +0000
                Re: [ On topic, amazingtly ]: labels and declarations David Brown <david.brown@hesbynett.no> - 2019-03-18 13:41 +0100
                Re: [ On topic, amazingtly ]: labels and declarations fir <profesor.fir@gmail.com> - 2019-03-18 06:54 -0700
                Re: [ On topic, amazingtly ]: labels and declarations fir <profesor.fir@gmail.com> - 2019-03-18 07:05 -0700
                Re: [ On topic, amazingtly ]: labels and declarations fir <profesor.fir@gmail.com> - 2019-03-18 09:07 -0700
            Re: [ On topic, amazingtly ]: labels and declarations Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-18 06:46 -0700
              Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 07:25 -0700
        Re: [ On topic, amazingtly ]: labels and declarations Manfred <noname@add.invalid> - 2019-03-21 17:48 +0100
          Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-21 10:04 -0700
            Re: [ On topic, amazingtly ]: labels and declarations fir is a sexy shemale <cdalten@gmail.com> - 2019-03-21 10:34 -0700
            Re: [ On topic, amazingtly ]: labels and declarations Jorgen Grahn <grahn+nntp@snipabacken.se> - 2019-03-21 20:19 +0000
              Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-21 14:29 -0700
                Re: [ On topic, amazingtly ]: labels and declarations Chad <cdalten@gmail.com> - 2019-03-22 10:15 -0700
                Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-22 13:58 -0700
                Re: [ On topic, amazingtly ]: labels and declarations Chad <cdalten@gmail.com> - 2019-03-22 15:10 -0700
                Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-22 15:31 -0700
              Re: [ On topic, amazingtly ]: labels and declarations David Brown <david.brown@hesbynett.no> - 2019-03-22 09:22 +0100
                Re: [ On topic, amazingtly ]: labels and declarations Chad <cdalten@gmail.com> - 2019-03-22 09:28 -0700
            Re: [ On topic, amazingtly ]: labels and declarations Manfred <invalid@add.invalid> - 2019-03-22 18:15 +0100
              Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-22 10:51 -0700
              Re: [ On topic, amazingtly ]: labels and declarations Keith Thompson <kst-u@mib.org> - 2019-03-22 11:31 -0700
                Re: [ On topic, amazingtly ]: labels and declarations Manfred <noname@add.invalid> - 2019-03-23 17:43 +0100
                Re: [ On topic, amazingtly ]: labels and declarations Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-23 13:36 -0700
                Re: [ On topic, amazingtly ]: labels and declarations Richard Damon <Richard@Damon-Family.org> - 2019-03-23 17:37 -0400
                Re: [ On topic, amazingtly ]: labels and declarations Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-25 09:18 -0700
              Re: [ On topic, amazingtly ]: labels and declarations James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-03-22 12:59 -0700
                Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-22 14:03 -0700
                Re: [ On topic, amazingtly ]: labels and declarations David Brown <david.brown@hesbynett.no> - 2019-03-23 12:44 +0100
                Re: [ On topic, amazingtly ]: labels and declarations Robert Wessel <robertwessel2@yahoo.com> - 2019-03-24 10:10 -0500
                Re: [ On topic, amazingtly ]: labels and declarations Manfred <noname@add.invalid> - 2019-03-23 17:48 +0100
                Re: [ On topic, amazingtly ]: labels and declarations James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-03-25 11:32 -0700
          Re: [ On topic, amazingtly ]: labels and declarations Robert Wessel <robertwessel2@yahoo.com> - 2019-03-21 22:22 -0500
            Re: [ On topic, amazingtly ]: labels and declarations Manfred <noname@add.invalid> - 2019-03-22 17:45 +0100
              Re: [ On topic, amazingtly ]: labels and declarations Keith Thompson <kst-u@mib.org> - 2019-03-22 11:13 -0700
                Re: [ On topic, amazingtly ]: labels and declarations Manfred <noname@add.invalid> - 2019-03-23 18:20 +0100
                Re: [ On topic, amazingtly ]: labels and declarations Keith Thompson <kst-u@mib.org> - 2019-03-23 11:57 -0700
                Re: [ On topic, amazingtly ]: labels and declarations James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-03-25 10:58 -0700
                Re: [ On topic, amazingtly ]: labels and declarations Keith Thompson <kst-u@mib.org> - 2019-03-25 13:17 -0700
      Re: [ On topic, amazingtly ]: labels and declarations Keith Thompson <kst-u@mib.org> - 2019-03-17 16:16 -0700
        Re: [ On topic, amazingtly ]: labels and declarations Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2019-03-17 19:29 -0400
          Re: [ On topic, amazingtly ]: labels and declarations Keith Thompson <kst-u@mib.org> - 2019-03-17 16:49 -0700
            Re: [ On topic, amazingtly ]: labels and declarations Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2019-03-17 19:51 -0400
            Re: [ On topic, amazingtly ]: labels and declarations Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-17 17:41 -0700
              Re: [ On topic, amazingtly ]: labels and declarations Richard Damon <Richard@Damon-Family.org> - 2019-03-17 22:53 -0400
                Re: [ On topic, amazingtly ]: labels and declarations Keith Thompson <kst-u@mib.org> - 2019-03-17 21:08 -0700
                Re: [ On topic, amazingtly ]: labels and declarations Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-17 21:40 -0700
                Re: [ On topic, amazingtly ]: labels and declarations gazelle@shell.xmission.com (Kenny McCormack) - 2019-03-18 05:03 +0000
                Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 02:30 -0700
                Re: [ On topic, amazingtly ]: labels and declarations Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-18 06:32 -0700
                Re: [ On topic, amazingtly ]: labels and declarations gazelle@shell.xmission.com (Kenny McCormack) - 2019-03-18 16:06 +0000
                Re: [ On topic, amazingtly ]: labels and declarations Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-17 22:19 -0700
        Re: [ On topic, amazingtly ]: labels and declarations Richard Damon <Richard@Damon-Family.org> - 2019-03-17 20:07 -0400
  Re: [ On topic, amazingtly ]: labels and declarations luser droog <luser.droog@gmail.com> - 2019-03-17 12:37 -0700
  Re: [ On topic, amazingtly ]: labels and declarations "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-18 11:00 +0800
    Re: [ On topic, amazingtly ]: labels and declarations "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-18 22:43 +0800
      Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 08:00 -0700
        Re: [ On topic, amazingtly ]: labels and declarations "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-19 13:11 +0800
          Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) gazelle@shell.xmission.com (Kenny McCormack) - 2019-03-19 05:27 +0000
            Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-19 14:40 +0800
            Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-19 04:39 -0700
              Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-19 19:44 +0800
                Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 05:11 -0700
                Re: Use of goto in high-level C programming "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-19 20:13 +0800
                Re: Use of goto in high-level C programming fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 05:42 -0700
                Re: Use of goto in high-level C programming "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-19 20:44 +0800
                Re: Use of goto in high-level C programming Wouter Verhelst <w@uter.be> - 2019-03-20 08:16 +0200
                Re: Use of goto in high-level C programming "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-20 19:16 +0800
              Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 05:13 -0700
                Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-19 05:56 -0700
                Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 06:30 -0700
                Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-19 06:54 -0700
                Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 07:12 -0700
                Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-19 12:03 -0700
                Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 13:33 -0700
  Re: [ On topic, amazingtly ]: labels and declarations fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 05:17 -0700
    Re: from programming to religion and then.... sex? "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-19 20:23 +0800
      Re: from programming to religion and then.... sex? fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 05:40 -0700
        Re: from programming to religion and then.... sex? "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-19 20:46 +0800
          Re: from programming to religion and then.... sex? fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 06:30 -0700
            Re: from programming to religion and then.... sex? "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-19 21:36 +0800
              Re: from programming to religion and then.... sex? fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 07:08 -0700
                Re: from programming to religion and then.... sex? "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-20 19:16 +0800
  Re: [ On topic, amazingtly ]: labels and declarations John Bode <jfbode1029@gmail.com> - 2019-03-19 14:58 -0700

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