From mboxrd@z Thu Jan  1 00:00:00 1970
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To: 9fans@cse.psu.edu
Cc: steve@localhost.localdomain
Subject: Re: [9fans] useful language extension, or no? 
In-Reply-To: Message from Sam <sah@softcardsystems.com> 
   of "Tue, 16 Jul 2002 11:05:58 EDT." <Pine.LNX.4.30.0207161101140.14125-100000@athena> 
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From: Steve Kilbane <steve@whitecrow.demon.co.uk>
Date: Tue, 16 Jul 2002 22:29:42 +0100
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> Suppose I'm not saying "why," but "why not."  IMO it's cleaner

I disagree. It's considerably more ambiguous. Your loop continuation
condition (i<NELS) may be failed by considerably more cases
than your trailing condition (i==NELS). What happens if your loop
body does "i=NELS+1"? What if your "i++" was actually something
like "i=arr[i]"? What if your continuation condition was
"i<NELS && j<NELS2"?

C's "for" is not like Pascal's FOR.

> and
> quite possibly more efficient

The pros and cons have already been discussed. I'd just like to
note that there's no particularly compelling reason why it would
generate different code from that which used the idiom. A good
optimiser would render them into the same internal form anyway.

"A good optimiser" is a subjective term, and Plan 9's C optimising
has already been discussed recent (Summary: it's good enough that
there are more important/interesting/useful things to work on),
but the point stands.

steve