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Re: Comma operator in for() statements

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From Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups comp.lang.c
Subject Re: Comma operator in for() statements
Date Fri, 27 Mar 2020 06:46:06 -0700
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luser droog <luser.droog@gmail.com> writes:

> [how to make for() variables be const]
>
> I've tried to shake the habit of seeing macros everywhere,
> but this is getting to the length where a macro might be an
> appropriate way to use this idiom.
>
> #define FOR_UP(IDX, INI, LIM, BODY)  \
>   for(  int IDX ## __LINE__ = (INI); \
>         IDX ## __LINE__ < (LIM);     \
>         ++ IDX ## __LINE__  ){       \
>     int const IDX = IDX ## __LINE__; \
>     BODY;                            \
>   }

Maybe so but this macro isn't it.

  (1) Type of iteration variable should be a parameter,
      not fixed.

  (2) The usage '## __LINE__' doesn't work.

  (3) The "test" and "increment" should both be more
      general.

  (4) Perhaps most important, the loop body should
      not be a parameter.  Ick and double ick.

Challenge:  write a macro definition that addresses each
of the above concerns.  Specifically with regard to point
(4), the macro expansion should act like a 'for(...)'
prefix, so the loop body statement comes after the macro
call, eg,

    P_FOR( int, i, 0, < 10, ++ ){
        sum += a[i];
    }

(Yes there are hints there for some of the other points.)

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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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