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

From	Manfred <noname@add.invalid>
Newsgroups	comp.lang.c
Subject	Re: [ On topic, amazingtly ]: labels and declarations
Date	2019-03-23 18:20 +0100
Organization	Aioe.org NNTP Server
Message-ID	<q75ps0$1sic$1@gioia.aioe.org> (permalink)
References	(3 earlier) <8gAjE.142392$tK1.4950@fx28.am4> <q70f9c$ar7$1@gioia.aioe.org> <f6l89el6s9sst13gt0tsc2idd8kpsn9cbr@4ax.com> <q733ed$25e$1@gioia.aioe.org> <lno962g4kb.fsf@kst-u.example.com>

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On 3/22/2019 7:13 PM, Keith Thompson wrote:
> Manfred <noname@add.invalid> writes:
>> On 3/22/2019 4:22 AM, Robert Wessel wrote:
>>>> This problem apparently follows from labels being neither statements nor
>>>> declarations, but instead entities of their own slapped into the
>>>> language to pair their ASM counterparts.
>>>> Today one may say they were not thought well enough in the beginning,
>>>> but considering the status of CS in the '70s it would have been probably
>>>> hard to foresee this kind of implications at the time, and hey, they
>>>> served the purpose so far.
>>>
>>> Labels are an optional prefix to a statement.
>>
>> i.e. a direct import from ASM, without further attempt for integration
>> with the language structure.
> 
> Not really.  The syntax and semantics of C's labels are similar to those
> of assembly language labels, but I'm not sure how else you'd define
> them.  There's not much you could do to integrate them more closely into
> the rest of the language.  Their syntax is defined using the same BNF as
> everything else:
> 
>      labeled-statement:
>          identifier : statement
>          case constant-expression : statement
>          default : statement

BNF describes the design choices of the language, it does not mean that 
such design is good.
Here it is shown that a label is defined to be part of a kind of 
statement - a labeled-statement.
This means that:
1) The definition of statement had to be augmented with an additional 
type thereof: a labeled-statement
2) To allow for fitting this assembly-like entity.

Considering that the main building blocks of the C syntax are 
Declarations and Statements, the adopted choice /may/ [*] be seen as 
poor integration in that it does not fit labels into any of these, but 
instead the language lawmakers had to make a special kind of statement 
to allow for its insertion.
To me this hints some lack of uniformity in the language design.
On the other hand, the absence of a 'labeled-declaration' may show some 
lack of symmetry in the same design.

With a-posteriori knowledge, and after four decades of CS evolution, 
this choice appears to clash with a more modern C, where declarations 
may make sense to be labeled too.
This may have been avoided either by defining a label as a 'null 
statement', so a type of statement by itself, as Bart was suggesting, 
or, after your display of the formal syntax, by envisioning the 
possibility for a 'labeled-declaration'

[*] All of this can be argued today, as said, after more than 40 years 
of C development, so it would make no sense to say that the current 
status was a poor choice in the design of the language, in particular 
considering /when/ the language was designed.
It may only hint to some possible better choice that could have been 
made, but that in fact did not hinder at all the success of the language 
itself.
Even more since the solution of adding a null statement like "label: ;" 
is pretty simple and concise.

> 
> Compare that to the preprocessor, which really isn't tightly integrated
> into the language structure.
>

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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