Re: New C operator -- would it be a good idea?

From	"Scott Fluhrer" <sfluhrer@ix.netcom.com>
Newsgroups	comp.lang.c
References	<fe55af6c-8fd3-4130-9a6e-6838ff600111@q7g2000pbj.googlegroups.com>
Subject	Re: New C operator -- would it be a good idea?
Message-ID	<1347388093.969136@rcdn-nntpcache-3> (permalink)
Organization	cisco.com
Date	2012-09-11 14:27 -0400

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"mike3" <mike4ty4@yahoo.com> wrote in message 
news:fe55af6c-8fd3-4130-9a6e-6838ff600111@q7g2000pbj.googlegroups.com...
> Hi.
>
> I was wondering about this. I saw this posting on this site:
>
> http://stackoverflow.com/questions/1642028/what-is-the-name-of-this-operator
>
> where they were mentioning a fake "operator", an artifact of how the C
> language is interpreted, that looked like it caused the value of a
> variable to "go to" another. Namely, "x --> 0" in the code was just
> "x-- > 0", giving it the appearance of having the effect of
> "incrementing x toward 0". Now, I was wondering: would this be a good
> idea for a new real operator for the C language? Namely, "a -->
> b" (and "b <-- a") as real operators that could increment a toward b.
> Or would it be pretty worthless?

Whenever you're talking about a language extension, you need to consider 
some things:

- How much would this extension improve the language?  Would it make it 
easier to make maintainable, reliable programs?  Would it allow the compiler 
to improve the code generation for a significant number of programs?

- How much would this extension cost?  After all, extending the language 
implies that every programmer needs to remember this additional operator 
(even if they don't use it themselves, they may run into it while reading 
other people's programs).  In addition, adding this would require that every 
compiler also implement it.

So, what's the result of this cost/benefit analysis?  Well, I don't see much 
benefit at all; I can't think of that many places where this would be 
heavily used, and where it is, this long-hand form would look quite 
appropriate, both for the humans reading/maintaining the code, and the 
compiler processing the code:

   if (b < a) {
       a -= 1;   /* b is below; move a somewhat closer to b */
   } else if (b > a) {
       a += 1;   /* b is above, move a somewhat closer to b */
   } else {
       /* a == b; keep a where it is */
   }

So, virtually no benefit at some nonzero cost; it doesn't look worth it to 
me.

-- 
poncho

Thread

New C operator -- would it be a good idea? mike3 <mike4ty4@yahoo.com> - 2012-09-10 12:48 -0700
  Re: New C operator -- would it be a good idea? "Scott Fluhrer" <sfluhrer@ix.netcom.com> - 2012-09-11 14:27 -0400
    Re: New C operator -- would it be a good idea? "christian.bau" <christian.bau@cbau.wanadoo.co.uk> - 2012-09-11 16:53 -0700
  Re: New C operator -- would it be a good idea? Kaz Kylheku <kaz@kylheku.com> - 2012-09-11 19:24 +0000
    Re: New C operator -- would it be a good idea? "Scott Fluhrer" <sfluhrer@ix.netcom.com> - 2012-09-11 15:56 -0400
      Re: New C operator -- would it be a good idea? Keith Thompson <kst-u@mib.org> - 2012-09-11 14:15 -0700
      Re: New C operator -- would it be a good idea? mike3 <mike4ty4@yahoo.com> - 2012-09-11 15:56 -0700
        Re: New C operator -- would it be a good idea? Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-09-12 00:56 -0700
          Re: New C operator -- would it be a good idea? "BartC" <bc@freeuk.com> - 2012-09-12 10:55 +0100
            Re: New C operator -- would it be a good idea? "io_x" <a@b.c.invalid> - 2012-09-13 07:47 +0200
              Re: New C operator -- would it be a good idea? "BartC" <bc@freeuk.com> - 2012-09-13 10:47 +0100
    Re: New C operator -- would it be a good idea? mike3 <mike4ty4@yahoo.com> - 2012-09-11 15:25 -0700
      Re: New C operator -- would it be a good idea? David Brown <david@westcontrol.removethisbit.com> - 2012-09-12 09:39 +0200
        Re: New C operator -- would it be a good idea? mike3 <mike4ty4@yahoo.com> - 2012-09-12 08:33 -0700
          Re: New C operator -- would it be a good idea? David Brown <david@westcontrol.removethisbit.com> - 2012-09-13 09:53 +0200
    Re: New C operator -- would it be a good idea? falk@rahul.net (Edward A. Falk) - 2012-09-12 17:43 +0000
      Re: New C operator -- would it be a good idea? mike3 <mike4ty4@yahoo.com> - 2012-09-12 15:35 -0700
      Re: New C operator -- would it be a good idea? Ike Naar <ike@iceland.freeshell.org> - 2012-09-13 06:34 +0000
        Re: New C operator -- would it be a good idea? "BartC" <bc@freeuk.com> - 2012-09-13 11:47 +0100
      Re: New C operator -- would it be a good idea? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-09-13 23:52 -0700
        Re: New C operator -- would it be a good idea? Ike Naar <ike@iceland.freeshell.org> - 2012-09-14 07:53 +0000
          Re: New C operator -- would it be a good idea? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-09-14 11:46 +0100
            Re: New C operator -- would it be a good idea? JohnF <john@please.see.sig.for.email.com> - 2012-09-14 13:17 +0000
          Re: New C operator -- would it be a good idea? John Bode <jfbode1029@gmail.com> - 2012-09-14 11:35 -0700
        Re: New C operator -- would it be a good idea? Keith Thompson <kst-u@mib.org> - 2012-09-14 02:04 -0700
        Re: New C operator -- would it be a good idea? Kaz Kylheku <kaz@kylheku.com> - 2012-09-14 21:11 +0000
      Re: New C operator -- would it be a good idea? Ben Pfaff <blp@cs.stanford.edu> - 2012-09-14 11:39 -0700
  Re: New C operator -- would it be a good idea? "BartC" <bc@freeuk.com> - 2012-09-11 22:32 +0100
    Re: New C operator -- would it be a good idea? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-09-11 15:19 -0700
  Re: New C operator -- would it be a good idea? gordonb.22y0w@burditt.org (Gordon Burditt) - 2012-09-11 17:27 -0500
    Re: New C operator -- would it be a good idea? mike3 <mike4ty4@yahoo.com> - 2012-09-11 18:51 -0700
      Re: New C operator -- would it be a good idea? "BartC" <bc@freeuk.com> - 2012-09-12 10:49 +0100
      Re: New C operator -- would it be a good idea? Greg Martin <greg@softsprocket.com> - 2012-09-12 23:23 -0700
        Re: New C operator -- would it be a good idea? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-09-13 12:08 +0100
          Re: New C operator -- would it be a good idea? Keith Thompson <kst-u@mib.org> - 2012-09-13 15:20 -0700
      Re: New C operator -- would it be a good idea? gordonb.h093l@burditt.org (Gordon Burditt) - 2012-09-14 15:13 -0500
  Re: New C operator -- would it be a good idea? Rui Maciel <rui.maciel@gmail.com> - 2012-09-14 20:38 +0100

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