Path: utzoo!utgpu!water!watmath!clyde!bellcore!faline!ulysses!allegra!alice!ark
From: ark@alice.UUCP
Newsgroups: comp.lang.c
Subject: Re: C sintax
Message-ID: <7655@alice.UUCP>
Date: 26 Jan 88 16:17:58 GMT
References: <7072@brl-smoke.ARPA> <7160@brl-smoke.ARPA> <3932@hoptoad.uucp> <4080@june.cs.washington.edu>
Organization: AT&T Bell Laboratories, Liberty Corner NJ
Lines: 26
Posted: Tue Jan 26 11:17:58 1988

In article <4080@june.cs.washington.edu>, pardo@uw-june.UUCP writes:
> ( This isn't related to anything, but I've been unable to figure )
> ( out a mail path to the guy who asked, and I wanted to answer   )
> 
> >> 	;-D on  (My favorite sintax: switch(x+=*a+++*b){...})  Pardo
> >
> >Boy, you've got that. That's a sin, or should be.
> >What, precisely, does x+=*a+++*b mean?
> 
> Well, actually it is ambiguous.  There are 2 (or more?) ways to parse
> it.  I'm not sure the behavior is defined from lexer to lexer as to
> which one is preferred.

It's not ambiguous: C lexical analysis is defined by "maximal munch."

There is one issue, though: whether this is run on a C compiler
in which =* is a token (ancient).  If so, then += is probably
defined as two tokens as well.  On such an ancient compiler, it means

	x + =* a ++ + * b

which is illegal.  On more modern compilers, it means

	x += * a ++ + * b

with no ambiguity.