From owner-freebsd-current  Wed Jan 27 18:43:33 1999
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Date: Wed, 27 Jan 1999 21:43:21 -0500 (EST)
From: Brian Feldman <green@unixhelp.org>
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To: Peter Jeremy <peter.jeremy@auss2.alcatel.com.au>
cc: current@FreeBSD.ORG
Subject: Re: btokup() macro in sys/malloc.h
In-Reply-To: <99Jan28.131753est.40347@border.alcanet.com.au>
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On Thu, 28 Jan 1999, Peter Jeremy wrote:

> Matthew Dillon <dillon@apollo.backplane.com> wrote:
> >:>     NEW
> >:> 
> >:> #define btokup(addr)    (&kmemusage[((caddr_t)(addr) - kmembase) >> PAGE_SHIFT])
> >:
> >:The added parentheses don't make any difference, semantically.  This
> >:change probably wouldn't meet the criteria spelled out in style(9):
> >
> >    Then style(9) needs to be updated, because we have to add parenthesis
> >    to be able to not get warnings with -Wall.
> 
> I'll support that.  The example given in style(9):
> 
> 	a = b->c[0] + ~d == (e || f) || g && h ? i : j >> 1;
> 
> should rate as an entry in the Obfuscated C competition rather than
> an example of maintainable code.
> 
> style(9) should emphasize legibility and maintainability, rather than
> minimizing the number of extraneous (from the compiler's perspective)
> parenthesis.  The code you're writing has to be maintained for many years
> - and the maintainers will not always have your in-depth expertise.
> The code also forms a `reference implementation' for someone who wants
> to do something similar.

Here's another vote from someone who uses liberal parentheses! I think of it
like this: it may be correct, but if I can't understand it after I've written
it, what good is the code? Saving a few bytes isn't worth obfuscating code.
Style(9) should /dons flame-retardant suit/ encourage usage of extra parens
that make code more readable to humans.

> 
> Peter
> 
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