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Groups > comp.lang.c > #150793

Re: Comma operator in for() statements

From David Brown <david.brown@hesbynett.no>
Newsgroups comp.lang.c
Subject Re: Comma operator in for() statements
Date 2020-03-24 10:30 +0100
Organization A noiseless patient Spider
Message-ID <r5ck0i$e8$1@dont-email.me> (permalink)
References (17 earlier) <87eetirfyb.fsf@nosuchdomain.example.com> <ecfe4b65-d4d4-4ecc-adbc-aedb90638692@googlegroups.com> <871rpirdt3.fsf@nosuchdomain.example.com> <5788dcca-ca28-4fb4-b454-89436c601d0c@googlegroups.com> <87wo7aps7r.fsf@nosuchdomain.example.com>

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On 24/03/2020 00:27, Keith Thompson wrote:

> 
> If somebody came up with a more restrictive kind of loop that covered
> most cases and was less error-prone, I might not object to adding it to
> a future version of the language -- *in addition to* C's existing for
> loop, not replacing it.
> 

If I were to choose something to add to the for-loop syntax, I'd like:

	for (const int i = 0; i < N; i++) {
		...
	}

to have the same meaning as:

	for (const int i = 0; i < N; i++) {
		const int i_ = i;
		const int i = i_;
		...
	}


The first version is currently a constraint violation since it tries to 
increment a variable that is declared "const".  I'm not sure if that 
means the syntax here could be re-used to get the effect I am looking 
for.  If not, I suppose an alternative syntax could be found.

The idea here is to lock the loop variable inside the loop, so that it 
can only be changed in the iterator part of the for-statement.

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Thread

Comma operator in for() statements Geoff <geoff@invalid.invalid> - 2020-03-21 19:51 -0700
  Re: Comma operator in for() statements Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-03-22 03:31 +0000
    Re: Comma operator in for() statements Geoff <geoff@invalid.invalid> - 2020-03-21 23:17 -0700
      Re: Comma operator in for() statements Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-03-22 12:00 +0000
        Re: Comma operator in for() statements Geoff <geoff@invalid.invalid> - 2020-03-22 08:57 -0700
          Re: Comma operator in for() statements Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-03-22 16:20 +0000
            Re: Comma operator in for() statements Geoff <geoff@invalid.invalid> - 2020-03-22 14:02 -0700
              Re: Comma operator in for() statements Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-03-22 21:26 +0000
    Re: Comma operator in for() statements David Brown <david.brown@hesbynett.no> - 2020-03-22 10:25 +0100
    Re: Comma operator in for() statements Richard Damon <Richard@Damon-Family.org> - 2020-03-22 08:27 -0400
      Re: Comma operator in for() statements Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-03-22 16:31 +0000
  Re: Comma operator in for() statements James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-03-22 00:33 -0400
  Re: Comma operator in for() statements Bart <bc@freeuk.com> - 2020-03-22 12:23 +0000
    Re: Comma operator in for() statements James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-03-22 05:47 -0700
      Re: Comma operator in for() statements Bart <bc@freeuk.com> - 2020-03-22 14:17 +0000
        Re: Comma operator in for() statements felix@palmen-it.de (Felix Palmen) - 2020-03-22 15:55 +0100
          Re: Comma operator in for() statements Bart <bc@freeuk.com> - 2020-03-22 15:01 +0000
            Re: Comma operator in for() statements felix@palmen-it.de (Felix Palmen) - 2020-03-22 16:05 +0100
              Re: Comma operator in for() statements Bart <bc@freeuk.com> - 2020-03-22 16:46 +0000
                Re: Comma operator in for() statements felix@palmen-it.de (Felix Palmen) - 2020-03-22 18:14 +0100
                Re: Comma operator in for() statements James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-03-22 11:42 -0700
                Re: Comma operator in for() statements Bart <bc@freeuk.com> - 2020-03-22 22:03 +0000
                Re: Comma operator in for() statements James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-03-22 23:51 -0700
                Re: Comma operator in for() statements Bart <bc@freeuk.com> - 2020-03-23 14:37 +0000
                Re: Comma operator in for() statements Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-03-23 08:41 -0700
                Re: Comma operator in for() statements Guillaume <message@bottle.org> - 2020-03-23 16:53 +0100
                Re: Comma operator in for() statements Bart <bc@freeuk.com> - 2020-03-23 16:31 +0000
                Re: Comma operator in for() statements Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-03-23 16:48 +0000
                Re: Comma operator in for() statements Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-03-23 09:53 -0700
                Re: Comma operator in for() statements David Brown <david.brown@hesbynett.no> - 2020-03-23 18:59 +0100
                Re: Comma operator in for() statements Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-03-23 11:23 -0700
                Re: Comma operator in for() statements Bart <bc@freeuk.com> - 2020-03-23 19:51 +0000
                Re: Comma operator in for() statements James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-03-23 14:28 -0700
                Re: Comma operator in for() statements Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-03-23 13:09 -0700
                Re: Comma operator in for() statements Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-03-23 13:20 -0700
                Re: Comma operator in for() statements scott@slp53.sl.home (Scott Lurndal) - 2020-03-23 20:26 +0000
                Re: Comma operator in for() statements Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-03-23 13:55 -0700
                Re: Comma operator in for() statements Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-03-23 15:43 -0700
                Re: Comma operator in for() statements Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-03-23 16:27 -0700
                Re: Comma operator in for() statements Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-03-23 17:13 -0700
                Re: Comma operator in for() statements Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-03-23 21:11 -0700
                Re: Comma operator in for() statements Bart <bc@freeuk.com> - 2020-03-24 00:19 +0000
                Re: Comma operator in for() statements David Brown <david.brown@hesbynett.no> - 2020-03-24 10:30 +0100
                Re: Comma operator in for() statements Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-03-24 03:07 -0700
                Re: Comma operator in for() statements David Brown <david.brown@hesbynett.no> - 2020-03-24 11:37 +0100
                Re: Comma operator in for() statements Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-03-24 11:18 +0000
                Re: Comma operator in for() statements David Brown <david.brown@hesbynett.no> - 2020-03-24 13:23 +0100
                Re: Comma operator in for() statements Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-03-24 14:53 +0000
                Re: Comma operator in for() statements David Brown <david.brown@hesbynett.no> - 2020-03-25 10:35 +0100
                Re: Comma operator in for() statements Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-03-25 11:12 +0000
                Re: Comma operator in for() statements Ike Naar <ike@sdf.lonestar.org> - 2020-03-26 19:21 +0000
                Re: Comma operator in for() statements luser droog <luser.droog@gmail.com> - 2020-03-24 21:22 -0700
                Re: Comma operator in for() statements Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-03-27 06:46 -0700
                Re: Comma operator in for() statements luser droog <luser.droog@gmail.com> - 2020-03-28 01:01 -0700
                Re: Comma operator in for() statements Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-03-28 11:26 +0000
                Re: Comma operator in for() statements luser droog <luser.droog@gmail.com> - 2020-03-28 14:22 -0700
                Re: Comma operator in for() statements Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-04-02 08:12 -0700
                Re: Comma operator in for() statements luser droog <luser.droog@gmail.com> - 2020-04-02 12:21 -0700
                Re: Comma operator in for() statements Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-04-02 19:43 -0700
                Re: Comma operator in for() statements Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-03-24 12:56 -0700
                Re: Comma operator in for() statements Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-03-24 23:44 +0000
                Re: Comma operator in for() statements James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-03-23 17:10 -0700
                Re: Comma operator in for() statements David Brown <david.brown@hesbynett.no> - 2020-03-24 10:17 +0100
                Re: Comma operator in for() statements Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-03-23 18:13 +0000
                Re: Comma operator in for() statements James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-03-23 09:32 -0700
                Re: Comma operator in for() statements David Brown <david.brown@hesbynett.no> - 2020-03-23 19:06 +0100
                Re: Comma operator in for() statements Richard Damon <Richard@Damon-Family.org> - 2020-03-23 13:23 -0400
                Re: Comma operator in for() statements Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-03-23 10:33 -0700
                Re: Comma operator in for() statements Guillaume <message@bottle.org> - 2020-03-23 18:34 +0100
                Re: Comma operator in for() statements Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-03-23 18:18 +0000
                Re: Comma operator in for() statements Ike Naar <ike@sdf.lonestar.org> - 2020-03-23 22:29 +0000
                Re: Comma operator in for() statements Bart <bc@freeuk.com> - 2020-03-23 23:13 +0000
            Re: Comma operator in for() statements richard@cogsci.ed.ac.uk (Richard Tobin) - 2020-03-22 15:17 +0000
          Re: Comma operator in for() statements nobody@example.org (Scott) - 2020-03-22 16:16 +0000
            Re: Comma operator in for() statements Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2020-03-23 07:22 -0700
            Re: Comma operator in for() statements Guillaume <message@bottle.org> - 2020-03-25 15:10 +0100
              Re: Comma operator in for() statements Jorgen Grahn <grahn+nntp@snipabacken.se> - 2020-03-25 15:18 +0000
          Re: Comma operator in for() statements Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-03-22 16:27 +0000
          Re: Comma operator in for() statements James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-03-22 15:07 -0400
        Re: Comma operator in for() statements James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-03-22 11:33 -0700
      Re: Comma operator in for() statements Anton Shepelev <anton.txt@g{oogle}mail.com> - 2020-03-24 20:25 +0300
        Re: Comma operator in for() statements Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-03-24 23:25 +0000
          Re: Comma operator in for() statements Bart <bc@freeuk.com> - 2020-03-25 01:55 +0000
            Re: Comma operator in for() statements Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-03-25 11:01 +0000
          Re: Comma operator in for() statements Anton Shepelev <anton.txt@g{oogle}mail.com> - 2020-03-25 14:59 +0300
            Re: Comma operator in for() statements Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-03-27 07:42 -0700
              Re: Comma operator in for() statements Bart <bc@freeuk.com> - 2020-03-27 14:51 +0000
                Re: Comma operator in for() statements Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-04-02 19:20 -0700
        Re: Comma operator in for() statements James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-03-24 20:01 -0400
          Re: Comma operator in for() statements Bart <bc@freeuk.com> - 2020-03-25 02:05 +0000
            Re: Comma operator in for() statements Bart <bc@freeuk.com> - 2020-03-25 15:13 +0000
          Re: Comma operator in for() statements Anton Shepelev <anton.txt@g{oogle}mail.com> - 2020-03-25 15:05 +0300
            Re: Comma operator in for() statements James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-03-25 10:04 -0400
    Re: Comma operator in for() statements David Brown <david.brown@hesbynett.no> - 2020-03-22 14:49 +0100
  Re: Comma operator in for() statements Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2020-03-22 09:24 -0600
    Re: Comma operator in for() statements Geoff <geoff@invalid.invalid> - 2020-03-22 14:51 -0700
      Re: Comma operator in for() statements James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-03-22 20:13 -0400
        Re: Comma operator in for() statements Geoff <geoff@invalid.invalid> - 2020-03-23 12:16 -0700
          Re: Comma operator in for() statements Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-03-23 13:16 -0700
          Re: Comma operator in for() statements James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-03-23 17:16 -0400
            Re: Comma operator in for() statements scott@slp53.sl.home (Scott Lurndal) - 2020-03-23 22:40 +0000
  Re: Comma operator in for() statements Guillaume <message@bottle.org> - 2020-03-22 17:31 +0100
    Re: Comma operator in for() statements Geoff <geoff@invalid.invalid> - 2020-03-22 12:28 -0700
      Re: Comma operator in for() statements James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-03-22 15:35 -0400
        Re: Comma operator in for() statements Geoff <geoff@invalid.invalid> - 2020-03-22 13:43 -0700
  Re: Comma operator in for() statements Les Cargill <lcargill99@comcast.com> - 2020-03-22 13:50 -0500
    Re: Comma operator in for() statements Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-03-22 19:25 +0000
      Re: Comma operator in for() statements David Brown <david.brown@hesbynett.no> - 2020-03-22 21:52 +0100
        Re: Comma operator in for() statements Ben Bacarisse <ben.usenet@bsb.me.uk> - 2020-03-22 21:15 +0000
          Re: Comma operator in for() statements David Brown <david.brown@hesbynett.no> - 2020-03-23 09:17 +0100
  Re: Comma operator in for() statements Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-03-27 08:02 -0700

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