Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!ernie.Berkeley.EDU!jas
From: jas@ernie.Berkeley.EDU (Jim Shankland)
Newsgroups: comp.lang.c
Subject: Re: Compiler Error?
Keywords: "?:" precedence cc pcc assignment 43BSD SunOS
Message-ID: <28033@ucbvax.BERKELEY.EDU>
Date: 15 Feb 89 17:03:41 GMT
References: <683@sbsvax.UUCP>
Sender: usenet@ucbvax.BERKELEY.EDU
Reply-To: jas@ernie.Berkeley.EDU.UUCP (Jim Shankland)
Organization: University of California, Berkeley
Lines: 21

In article <683@sbsvax.UUCP> greim@sbsvax.UUCP (Michael Greim) writes:
>This is about pre-ANSI C.
>
> [Is the following legal C?]
>		(j = 2) ? k = 3 : 4;

I.e., is the assignment statement between the ? and the : legal, given
that = has lower precedence than ?:.

This issue comes up periodically.  The answer is unclear.  K & R
doesn't rightly say whether this is legal, though people have made
casuistic arguments on both sides.  I *will* note that it's
unambiguous and easily parsable, so perhaps there's no reason to
disallow it.  No doubt the pANS has resolved this one way or the other.
Meanwhile, I claim:  if you're writing a compiler, allow it; if you're
writing code, don't use it.

Jim Shankland
jas@ernie.berkeley.edu

"I've been walking in a river all my life, and now my feet are wet"