From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <zsh-workers-return-25282-mason-zsh=primenet.com.au@sunsite.dk>
Received: (qmail 5537 invoked from network); 15 Jul 2008 07:59:20 -0000
X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on f.primenet.com.au
X-Spam-Level: 
X-Spam-Status: No, score=-2.6 required=5.0 tests=AWL,BAYES_00 autolearn=ham
	version=3.2.5
Received: from news.dotsrc.org (HELO a.mx.sunsite.dk) (130.225.247.88)
  by ns1.primenet.com.au with SMTP; 15 Jul 2008 07:59:20 -0000
Received-SPF: none (ns1.primenet.com.au: domain at sunsite.dk does not designate permitted sender hosts)
Received: (qmail 20488 invoked from network); 15 Jul 2008 07:59:07 -0000
Received: from sunsite.dk (130.225.247.90)
  by a.mx.sunsite.dk with SMTP; 15 Jul 2008 07:59:07 -0000
Received: (qmail 495 invoked by alias); 15 Jul 2008 07:59:04 -0000
Mailing-List: contact zsh-workers-help@sunsite.dk; run by ezmlm
Precedence: bulk
X-No-Archive: yes
X-Seq: 25282
Received: (qmail 482 invoked from network); 15 Jul 2008 07:59:04 -0000
Received: from bifrost.dotsrc.org (130.225.254.106)
  by sunsite.dk with SMTP; 15 Jul 2008 07:59:04 -0000
Received: from mail.o2.co.uk (vader.london.02.net [82.132.130.150])
	by bifrost.dotsrc.org (Postfix) with ESMTP id 66FF880525AB
	for <zsh-workers@sunsite.dk>; Tue, 15 Jul 2008 09:59:00 +0200 (CEST)
Received: from sc.homeunix.net (78.105.216.138) by mail.o2.co.uk (8.0.013.3) (authenticated as stephane.chazelas)
        id 4863700403959808; Tue, 15 Jul 2008 08:58:59 +0100
Received: from chazelas by sc.homeunix.net with local (Exim 4.69)
	(envelope-from <stephane_chazelas@yahoo.fr>)
	id 1KIfR4-0001T3-0b; Tue, 15 Jul 2008 08:58:58 +0100
Date: Tue, 15 Jul 2008 08:58:57 +0100
From: Stephane Chazelas <Stephane_Chazelas@yahoo.fr>
To: Jaime Vargas <jev@mac.com>
Cc: Zsh hackers list <zsh-workers@sunsite.dk>
Subject: Re: Idiom
Message-ID: <20080715075857.GA5030@sc.homeunix.net>
Mail-Followup-To: Jaime Vargas <jev@mac.com>,
	Zsh hackers list <zsh-workers@sunsite.dk>
References: <398A2623-A473-4DFA-89C8-91716D1405AB@mac.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-15
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <398A2623-A473-4DFA-89C8-91716D1405AB@mac.com>
User-Agent: Mutt/1.5.16 (2007-09-19)
X-Virus-Scanned: ClamAV 0.92.1/7716/Tue Jul 15 04:34:17 2008 on bifrost
X-Virus-Status: Clean

On Mon, Jul 14, 2008 at 05:34:05PM -0400, Jaime Vargas wrote:
> Is there a better way to setup the ${mask_octects} array?
> Without the back-ticks the expression constructs an array of one element.
>
> -- Jaime
>
> #!/bin/zsh
> declare -A cidr_to_mask
> cidr_to_mask=(
>   16    255.255.0.0
>   17    255.255.128.0
>   18    255.255.192.0
>   19    255.255.224.0
>   20    255.255.240.0
>   21    255.255.248.0
>   22    255.255.252.0
>   23    255.255.254.0
>   24    255.255.255.0
>   25    255.255.255.128
>   26    255.255.255.192
>   27    255.255.255.224
>   28    255.255.255.240
>   29    255.255.255.248
>   30    255.255.255.252
>   31    255.255.255.254
>   32    255.255.255.255
> )
>
> set -A mask_octects `echo ${cidr_to_mask[22]//./ }`

Maybe something like:

set-mask_octects() {
  local mask
  (( mask = (2 ** $1 - 1) << (32 - $1)))
  mask_octects=()
  repeat 4 {
    mask_octects=($((mask & 255)) $mask_octects)
    (( mask = mask >> 8 ))
  }
  return 0
}

-- 
Stéphane