Groups > comp.lang.c > #141944

Re: Remembering C's operator precedence rules

From	Keith Thompson <kst-u@mib.org>
Newsgroups	comp.lang.c
Subject	Re: Remembering C's operator precedence rules
Date	2019-03-13 15:24 -0700
Organization	None to speak of
Message-ID	<lnwol2jtu7.fsf@kst-u.example.com> (permalink)
References	<87lg1o9efx.fsf@bsb.me.uk> <1bh8cb93bi.fsf@pfeifferfamily.net> <86sgvqr96y.fsf@mailhub.linuxsc.com> <mgbiE.394290$Apg.172496@fx36.am4>

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Bart <bc@freeuk.com> writes:
[...]
> People want to write code so that it is clear to everyone else. 
> Including those more used to other languages which have different 
> precedences.
>
> There is NO advantage to writing expressions whose meanings are 
> critically dependent on the relative precedences of &, | and ^.
>
> Plus, many operators just have the wrong precedence, so you want to 
> employ them in the most natural manner. And that requires parentheses.

I mostly agree.  I suspect we'd differ about how much readers can
reasonably be expected to know, but let's not get into that.

> Which, as a bonus, makes code more portable.

In what sense is it more portable?  If I write C code that depends
on all 15 precedence levels, it's likely to be difficult for
human readers to understand it, but every C compiler will parse
it correctly.  I've never heard of a C compiler having an operator
precedence bug.  It's just too easy to get it right.

If you mean "portable" in the sense that it's easier to translate
to a different language, that's hardly ever worth worrying about.
(And a lot of languages uses the same precedence levels as C.)

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Will write code for food.
void Void(void) { Void(); } /* The recursive call of the void */

Thread

Remembering C's operator precedence rules Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-09 16:53 +0000
  Re: Remembering C's operator precedence rules Richard Damon <Richard@Damon-Family.org> - 2019-03-09 15:21 -0500
    Re: Remembering C's operator precedence rules Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-09 21:41 +0000
  Re: Remembering C's operator precedence rules Keith Thompson <kst-u@mib.org> - 2019-03-09 12:32 -0800
    Re: Remembering C's operator precedence rules Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-09 21:21 +0000
      Re: Remembering C's operator precedence rules Richard Damon <Richard@Damon-Family.org> - 2019-03-09 16:42 -0500
        Re: Remembering C's operator precedence rules "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-09 14:01 -0800
      Re: Remembering C's operator precedence rules Keith Thompson <kst-u@mib.org> - 2019-03-09 14:17 -0800
        Re: Remembering C's operator precedence rules Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-10 00:42 +0000
  Re: Remembering C's operator precedence rules Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2019-03-09 13:54 -0700
    Re: Remembering C's operator precedence rules Bart <bc@freeuk.com> - 2019-03-09 21:37 +0000
      Re: Remembering C's operator precedence rules Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-09 22:01 +0000
      Re: Remembering C's operator precedence rules Richard Damon <Richard@Damon-Family.org> - 2019-03-09 18:59 -0500
        Re: Remembering C's operator precedence rules Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-13 09:26 -0700
    Re: Remembering C's operator precedence rules Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-13 10:11 -0700
      Re: Remembering C's operator precedence rules Bart <bc@freeuk.com> - 2019-03-13 17:40 +0000
        Re: Remembering C's operator precedence rules Keith Thompson <kst-u@mib.org> - 2019-03-13 15:24 -0700
          Re: Remembering C's operator precedence rules Bart <bc@freeuk.com> - 2019-03-13 23:43 +0000
            Re: Remembering C's operator precedence rules Keith Thompson <kst-u@mib.org> - 2019-03-13 17:43 -0700
        Re: Remembering C's operator precedence rules Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-18 08:53 -0700
      Re: Remembering C's operator precedence rules Wouter Verhelst <w@uter.be> - 2019-03-13 22:24 +0200
        Re: Remembering C's operator precedence rules Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-13 14:06 -0700
        Re: Remembering C's operator precedence rules Ian Collins <ian-news@hotmail.com> - 2019-03-14 14:28 +1300
          Re: Remembering C's operator precedence rules scott@slp53.sl.home (Scott Lurndal) - 2019-03-14 13:35 +0000
            Re: Remembering C's operator precedence rules Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-03-14 06:55 -0700
            Re: Remembering C's operator precedence rules Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-14 16:39 +0000
              Re: Remembering C's operator precedence rules scott@slp53.sl.home (Scott Lurndal) - 2019-03-14 17:37 +0000
                Re: Remembering C's operator precedence rules Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-14 20:42 +0000
              Re: Remembering C's operator precedence rules Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-03-14 10:42 -0700
                Re: Remembering C's operator precedence rules Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-14 23:08 +0000
                Re: Remembering C's operator precedence rules Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-03-15 02:53 -0700
                Re: Remembering C's operator precedence rules Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2019-03-15 17:52 -0600
  Re: Remembering C's operator precedence rules Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-13 12:56 -0700
  Re: Remembering C's operator precedence rules Jens Stuckelberger <Jens_Stuckelberger@nowhere.net> - 2019-03-13 20:14 +0000
  Re: Remembering C's operator precedence rules fir <profesor.fir@gmail.com> - 2019-03-19 14:17 -0700

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