Path: utzoo!attcan!uunet!cs.utexas.edu!yale!cmcl2!phri!marob!cowan
From: cowan@marob.masa.com (John Cowan)
Newsgroups: comp.std.c++
Subject: Re: Proposed Enhancement to select/case (yes, I know...)
Message-ID: <26E3C576.1C9B@marob.masa.com>
Date: 4 Sep 90 15:17:10 GMT
References: <BURLEY.90Aug30030645@world.std.com> <1420@lupine.NCD.COM>
Distribution: comp
Organization: ESCC, New York City
Lines: 24

In article <1420@lupine.NCD.COM> rfg@NCD.COM (Ron Guilmette) writes:
>Regarding "case lists", it seems clear that a simple syntax, i.e.:
>
>	case FOO,BAR:
>
>won't work because the separator comma could be parsed as the normal comma
>operator, which would mess up everything.

Other posters have also asserted this.  I don't see it.

K&R2, section A7.19, says "Constant expressions may not contain ... comma
operators."  Case expressions are constant expressions.  Therefore the
overloading of commas in a "case list" construction is not ambiguous,
although it might confuse humans.

Other posters have also pointed out that ranges of characters such as
'A' .. 'Z' are inherently unportable w/r/t character set.  This is true,
but ranges of enums remain safe and useful, since enums are guaranteed to
be assigned values left-to-right increasing by 1.  A large enum declaration
may be listed in order of logical groups, and then a range could be used to
test whether or not a particular enum variable had a range within the group.
-- 
cowan@marob.masa.com			(aka ...!hombre!marob!cowan)
			e'osai ko sarji la lojban