From owner-freebsd-hackers@FreeBSD.ORG  Mon Aug  1 18:02:58 2005
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
X-Original-To: freebsd-hackers@freebsd.org
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 19D8516A41F;
	Mon,  1 Aug 2005 18:02:58 +0000 (GMT)
	(envelope-from keramida@linux.gr)
Received: from aiolos.otenet.gr (aiolos.otenet.gr [195.170.0.93])
	by mx1.FreeBSD.org (Postfix) with ESMTP id 24EB743D45;
	Mon,  1 Aug 2005 18:02:56 +0000 (GMT)
	(envelope-from keramida@linux.gr)
Received: from beatrix.daedalusnetworks.priv (aris.bedc.ondsl.gr
	[62.103.39.226])
	by aiolos.otenet.gr (8.13.4/8.13.4/Debian-1) with SMTP id
	j71I2soG010942; Mon, 1 Aug 2005 21:02:54 +0300
Received: from beatrix.daedalusnetworks.priv (localhost [127.0.0.1])
	by beatrix.daedalusnetworks.priv (8.13.3+Sun/8.13.3) with ESMTP id
	j71I2sgG001213; Mon, 1 Aug 2005 21:02:54 +0300 (EEST)
Received: (from keramida@localhost)
	by beatrix.daedalusnetworks.priv (8.13.3+Sun/8.13.3/Submit) id
	j71I2s5V001212; Mon, 1 Aug 2005 21:02:54 +0300 (EEST)
Date: Mon, 1 Aug 2005 21:02:54 +0300
From: Giorgos Keramidas <keramida@linux.gr>
To: John Baldwin <jhb@freebsd.org>
Message-ID: <20050801180254.GB1176@beatrix.daedalusnetworks.priv>
References: <64511.68.95.232.238.1122917387.squirrel@68.95.232.238>
	<200508011355.19274.jhb@FreeBSD.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <200508011355.19274.jhb@FreeBSD.org>
Cc: freebsd-hackers@freebsd.org
Subject: Re: [patch] rc.d cleanup
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, 
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 01 Aug 2005 18:02:58 -0000

On 2005-08-01 13:55, John Baldwin <jhb@freebsd.org> wrote:
>On Monday 01 August 2005 01:29 pm, diz@linuxpowered.com wrote:
>> This patch effects most of the rc.d scripts that utilize simple IF
>> statements, converting them to logical AND/OR's instead. For example:
>>
>> if [ ! -f foo ]
>> then
>>     bar
>> fi
>>
>> Would simply become:
>>
>> [ -f foo ] || bar
>>
>> The exception (but not the rule) is for any situation where ELIF/ELSE is
>> required. In other words any exclusive conditional situations.
>>
>> I also applied this notion to many simple blocks of code wrapped around
>> non-exclusive IF statements, such as:
>>
>> [ -f foo ] && {
>>    command-list
>>    [...]
>> }
>
> The argument I would have against this is that it is a lot easier to
> read the 'if foo; then ; fi' style, esp. for folks used to using C,
> etc.  Shell scripts don't need to be overly obfuscated.

Ditto.  The if/then blocks may look superficial at first and entirely
redundant, but they really work much better then code like this:

	[ -f foo ] || bar

has to be extended to form a multiline statement.  Now, I know that one
can always write:

	[ -f foo ] || {
		[ -d bar ] && {
			blah
		}
	}

But this quickly gets too ugly for my taste.  The equivalent if/then
blocks:

	if [ ! -f foo ]; then
		if [ -d bar ]; then
			blah
		fi
	fi

or even, the similar:

	if [ ! -f foo ] && [ -d bar ]; then
		blah
	fi

Look much much prettier to the eyes of one who knows how to read both
shell scripts and C code.

- Giorgos