Date: Fri, 29 Jan 1999 10:49:12 +0000 (GMT) From: Doug Rabson <dfr@nlsystems.com> To: Sheldon Hearn <axl@iafrica.com> Cc: Greg Lehey <grog@lemis.com>, current@FreeBSD.ORG Subject: Re: btokup().. patch to STYLE(9) (fwd) Message-ID: <Pine.BSF.4.01.9901291044130.95594-100000@herring.nlsystems.com> In-Reply-To: <92584.917604304@axl.noc.iafrica.com>
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On Fri, 29 Jan 1999, Sheldon Hearn wrote:
>
>
> On Fri, 29 Jan 1999 20:01:23 +1030, Greg Lehey wrote:
>
> > > I can't imagine how unnecessary parens are going to improve
> > > "readability" for anyone who knows his/her operator precedence.
> >
> > What about the others?
>
> I'd like to know that people who don't know operator precedence are
> leaving the kernel code alone, eh? :-)
I am a kernel developer. I also sometimes forget some of the precedence
rules. Often enough that I use strict parenthesising when I use those
operators.
>
> > Remember, we're not talking about the writer now, we're talking about
> > the reader, who in the general case is not the same person.
>
> Operator precedence is not a matter of perspective. A different person,
> who knows his or her operator precedence, will find the expression as
> easy to read as the writer.
I don't agree. If you have to stop and think about the stupid precedence
rules three times in an expression, the expression is too complicated and
should be simplified.
>
> > Documentation is the castor oil of programming. Managers know it
> > must be good because the programmers hate it so much.
>
> I take this to mean "provide above your expression a comment that
> explains what you're doing", not "clutter your expression with
> unnecessary parens in case you've made a mistake that nobody will spot
> because you haven't commented your code properly."
>
> The reason I'm interested in this (now tiresome) thread is that I'd much
> rather have to read
>
> /*
> * Bail out if the time left to next transaction is less than
> * the duration of the previous transaction.
> */
> if (t % u - n % u < d % u) {
>
> than
>
> if (((t % u) - (n % u)) < (d % u)) {
This is a strawman. The original expression is perfectly fine (by my
rules). One could make a case for:
if ((t % u) - (n % u) < d % u)
>
> Giving folks the go-ahead to use parens as a form of documentation is
> misguided and will end in tears. MHO.
I don't agree, obviously.
--
Doug Rabson Mail: dfr@nlsystems.com
Nonlinear Systems Ltd. Phone: +44 181 442 9037
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