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Groups > comp.lang.c > #11348

Re: is the < operator transitive?

From Edward Rutherford <edward.p.rutherford79@REMOVETHIS.gmail.com>
Newsgroups comp.lang.c
Subject Re: is the < operator transitive?
Date 2011-10-07 20:23 +0000
Organization Aioe.org NNTP Server
Message-ID <j6nn3r$a73$1@speranza.aioe.org> (permalink)
References <4e8f3298$0$23280$426a74cc@news.free.fr> <j6nhku$s34$1@speranza.aioe.org> <lnehyowpuc.fsf@nuthaus.mib.org>

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Keith Thompson wrote:

> Edward Rutherford <edward.p.rutherford79@REMOVETHIS.gmail.com> writes:
> [...]
>> Python comparisons have the cool feature, that a<b<c is the same as
>> (a<b && b<c). So you can use normal notation for multiple comparisons.
>>
>> IMO it would be great if this could be backported to C.
> 
> The trouble is that ``a < b < c'' already has a meaning in C, so it
> would be an incompatible chnage.
> 
> Just as ``a + b + c'' is equivalent to ``(a + b) + c'' ``a < b < c'' is
> equivalent to ``(a < b) < c''.  In other words, it evaluates ``(a <b)'',
> which yields a value of 0 or 1, and compares that value to c.

This is just my point, Keith.

I find it hard to believe theres much existing code that deliberately 
uses this unintuitive interpretation. However it must be a cause of many 
bugs!

//EPR

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Thread

is the < operator transitive? Francois Grieu <fgrieu@gmail.com> - 2011-10-07 19:10 +0200
  Re: is the < operator transitive? Robert Wessel <robertwessel2@yahoo.com> - 2011-10-07 13:44 -0500
  Re: is the < operator transitive? Edward Rutherford <edward.p.rutherford79@REMOVETHIS.gmail.com> - 2011-10-07 18:50 +0000
    Re: is the < operator transitive? Keith Thompson <kst-u@mib.org> - 2011-10-07 12:42 -0700
      Re: is the < operator transitive? Edward Rutherford <edward.p.rutherford79@REMOVETHIS.gmail.com> - 2011-10-07 20:23 +0000
        Re: is the < operator transitive? Patrick Scheible <kkt@zipcon.net> - 2011-10-07 14:29 -0700
        Re: is the < operator transitive? Keith Thompson <kst-u@mib.org> - 2011-10-07 16:49 -0700
          Re: is the < operator transitive? Patrick Scheible <kkt@zipcon.net> - 2011-10-07 19:19 -0700
        Re: is the < operator transitive? Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-10-08 09:57 -0400
    Re: is the < operator transitive? "BartC" <bc@freeuk.com> - 2011-10-08 13:17 +0100
      Re: is the < operator transitive? Harald van Dijk <truedfx@gmail.com> - 2011-10-08 06:06 -0700
        Re: is the < operator transitive? "BartC" <bc@freeuk.com> - 2011-10-08 14:48 +0100
          Re: is the < operator transitive? Harald van Dijk <truedfx@gmail.com> - 2011-10-08 07:18 -0700
          Re: is the < operator transitive? "BartC" <bc@freeuk.com> - 2011-10-08 15:19 +0100
  Re: is the < operator transitive? Edward Rutherford <edward.p.rutherford79@REMOVETHIS.gmail.com> - 2011-10-07 18:50 +0000
    Re: is the < operator transitive? jacob navia <jacob@spamsink.net> - 2011-10-07 21:23 +0200
      Re: is the < operator transitive? Edward Rutherford <edward.p.rutherford79@REMOVETHIS.gmail.com> - 2011-10-07 20:24 +0000
        Re: is the < operator transitive? James Kuyper <jameskuyper@verizon.net> - 2011-10-07 16:40 -0400
          Re: is the < operator transitive? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-10-07 23:12 +0100
            Re: is the < operator transitive? Harald van Dijk <truedfx@gmail.com> - 2011-10-07 15:28 -0700
              Re: is the < operator transitive? Harald van Dijk <truedfx@gmail.com> - 2011-10-07 15:31 -0700
              Re: is the < operator transitive? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-10-07 23:36 +0100
                Re: is the < operator transitive? Patrick Scheible <kkt@zipcon.net> - 2011-10-07 16:18 -0700
                Re: is the < operator transitive? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-10-08 10:32 +0100
            Re: is the < operator transitive? James Kuyper <jameskuyper@verizon.net> - 2011-10-07 18:30 -0400
              Re: is the < operator transitive? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-10-08 00:21 +0100
                Re: is the < operator transitive? James Kuyper <jameskuyper@verizon.net> - 2011-10-07 21:33 -0400
                Re: is the < operator transitive? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-10-08 10:45 +0100
                Re: is the < operator transitive? James Kuyper <jameskuyper@verizon.net> - 2011-10-08 14:02 -0400
                Re: is the < operator transitive? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-10-08 21:49 +0100
                Re: is the < operator transitive? James Kuyper <jameskuyper@verizon.net> - 2011-10-08 17:17 -0400
                Re: is the < operator transitive? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-10-08 22:59 +0100
                Re: is the < operator transitive? James Kuyper <jameskuyper@verizon.net> - 2011-10-08 21:33 -0400
                Re: is the < operator transitive? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-10-09 09:09 +0100
                Re: is the < operator transitive? James Kuyper <jameskuyper@verizon.net> - 2011-10-09 07:00 -0400
                Re: is the < operator transitive? "BartC" <bc@freeuk.com> - 2011-10-09 01:12 +0100
                Re: is the < operator transitive? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-10-09 08:55 +0100
            Re: is the < operator transitive? Robert Wessel <robertwessel2@yahoo.com> - 2011-10-07 18:16 -0500
              Re: is the < operator transitive? David Thompson <dave.thompson2@verizon.net> - 2011-10-18 02:03 -0400
                Re: is the < operator transitive? Robert Wessel <robertwessel2@yahoo.com> - 2011-10-20 18:03 -0500
        Re: is the < operator transitive? Keith Thompson <kst-u@mib.org> - 2011-10-07 16:50 -0700
    Re: is the < operator transitive? "io_x" <a@b.c.invalid> - 2011-10-09 11:00 +0200
      Re: is the < operator transitive? Willem <willem@toad.stack.nl> - 2011-10-09 09:42 +0000
        Re: is the < operator transitive? Ike Naar <ike@sverige.freeshell.org> - 2011-10-09 12:20 +0000
          Re: is the < operator transitive? Willem <willem@toad.stack.nl> - 2011-10-09 12:40 +0000
            Re: is the < operator transitive? Ike Naar <ike@sverige.freeshell.org> - 2011-10-09 12:54 +0000
              Re: is the < operator transitive? Willem <willem@toad.stack.nl> - 2011-10-09 13:04 +0000
            Re: is the < operator transitive? "BartC" <bc@freeuk.com> - 2011-10-09 15:34 +0100
              Re: is the < operator transitive? Willem <willem@toad.stack.nl> - 2011-10-09 15:08 +0000
            Re: is the < operator transitive? Robert Wessel <robertwessel2@yahoo.com> - 2011-10-09 12:14 -0500
  Re: is the < operator transitive? James Kuyper <jameskuyper@verizon.net> - 2011-10-07 15:36 -0400
    Re: is the < operator transitive? Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-10-07 20:00 -0400
      Re: is the < operator transitive? James Kuyper <jameskuyper@verizon.net> - 2011-10-07 21:38 -0400
      Re: is the < operator transitive? Francois Grieu <fgrieu@gmail.com> - 2011-10-09 21:40 +0200
        Re: is the < operator transitive? Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-10-09 16:34 -0400
          Re: is the < operator transitive? Francois Grieu <fgrieu@gmail.com> - 2011-10-11 14:08 +0200
          Re: is the < operator transitive? Tim Rentsch <txr@alumni.caltech.edu> - 2012-01-24 16:14 -0800

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