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Groups > comp.lang.c > #150848
| From | Ike Naar <ike@sdf.lonestar.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Comma operator in for() statements |
| Date | 2020-03-26 19:21 +0000 |
| Organization | A noiseless patient Spider |
| Message-ID | <slrn3ocor7q06c.8h8.ike@sdf.lonestar.org> (permalink) |
| References | (18 earlier) <5788dcca-ca28-4fb4-b454-89436c601d0c@googlegroups.com> <87wo7aps7r.fsf@nosuchdomain.example.com> <r5ck0i$e8$1@dont-email.me> <87y2rq0zmy.fsf@bsb.me.uk> <r5cu3i$7ee$1@dont-email.me> |
On 2020-03-24, David Brown <david.brown@hesbynett.no> wrote:
> [...] I'd like to be
> able to re-define a variable within the same block, so that :
>
> {
> int x = 123;
> ...
> int x = 234;
> ...
> }
>
> would be valid, and treated as:
>
> {
> int x = 123;
> ...
> {
> int x = 234;
> ...
> }
> }
>
> That would allow you to "FIXATE" a variable declared earlier in the same
> block.
Using the same name for different things makes code harder to comprehend.
It may also introduce subtle errors when the code is refactored.
Imagine
int x = 123; /* definition x.1 */
foo(x); /* assumes x means x.1 */
/* ... long stretch of code not using x ... */
int x = 234; /* definition x.2 */
bar(x); /* assumes x means x.2 */
/* ... long stretch of code not using x ... */
zap(x); /* assumes x means x.2 */
Now suppose bar(x) is no longer needed, so the code is refactored
and the definition of x.2 and the bar(x) call are removed, not
realizing there's the zap(x) call futher down the line:
int x = 123; /* definition x.1 */
foo(x); /* assumes x means x.1 */
/* ... long stretch of code not using x ... */
/* ... long stretch of code not using x ... */
zap(x); /* assumes x means x.2, but now it means x.1; Whoops! */
> And for a final enhancement, I'd suggest that if a variable definition
> refers to its own identifier in its initialiser, and that identifier is
> in scope from before the definition, then the earlier identifier's value
> is used.
>
> Currently, if you write:
>
> int x = 123;
> {
> const int x = x;
> }
>
> then the second "x" has an unspecified value because the initialiser
> uses the newly defined "x" rather than the existing one. I'd like the
> specified value here be the value of the existing x.
>
> (I'm fairly certain that there would be complications in all these
> suggestions - I haven't made any study of more advanced cases.)
Again, using the same name for different things makes code harder to comprehend,
and, in my opinion, should be avoided when possible.
I think gcc even has a warning for this kind of thing (-Wshadow).
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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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