From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <c6c9ea6aebbab21da6eaaad7c2ceb6af@quanstro.net>
From: erik quanstrom <quanstro@quanstro.net>
Date: Sun,  6 Aug 2006 00:18:11 -0500
To: 9fans@cse.psu.edu
Subject: Re: [9fans] rc break
In-Reply-To: <65e36c043167477045d47b3d99da4b64@plan9.bell-labs.com>
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it looks like there are a number of cases in /rc/bin.  try "grep -n while".
most of them are argument parsing.  but then again, argument parsing
is a large part of what scripts do.  

the lack of a break also limits one from doing anything like this:
(snippit from an ancient byron's rc script for calculating the date
n days in the future.)

	# figure out what day we have by subtraction
	j = (Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec)
	c = ()
	for (i in 31 $feb 31 30 31 30 31 31 30 31 30 31) {
		c = ($c 1)
		if ( expr $i '>' $d >/dev/null) {
			break
		}
		d = `{expr $d - $i}
	}

perhaps something like 

	catch(done){
		for(i) switch($i){
		case -x
			xflag = 1;
		case -y
			yflag = 1;
		case *
			raise done
	}

would be better to implement.

- erik

On Sat Aug  5 18:43:19 CDT 2006, geoff@plan9.bell-labs.com wrote:
> I think this will work (modified from an rc script of mine):
> 
> while (! ~ $#* 0 && ~ $1 -* && ! ~ $1 --) {
> 	switch ($1) {
> 	case -a;	destsonly=yes
> 	case -b;	copies=($copies $2) ; shift
> 	case -c;	copies=($copies $user)
> 	case -v;	verbose=yes
> 	case -*
> 		echo usage: $0 '[-acv] [-b bcc] [file]...' >[1=2]
> 		exit usage
> 	}
> 	shift
> }
> # process $*, which now lacks options ...
> 
> I think this is the only situation in which I used to wish for `break'
> in rc, but it no longer seems worthwhile.