Re: [PATCH] Supplant the "while case ... break ;; esac" idiom

From: Pierre Habouzit <madcoder@debian.org>
Date: Sep 24, 2007, 08:04 UTC
Message-ID: <20070924080436.GB9112@artemis.corp>
In-Reply-To: <20070924080134.GA9112@artemis.corp>

On Mon, Sep 24, 2007 at 08:01:34AM +0000, Pierre Habouzit wrote:

Show 26 quoted lines

> On Mon, Sep 24, 2007 at 07:57:31AM +0000, David Kastrup wrote:
> > "David Symonds" <dsymonds@gmail.com> writes:
> > 
> > > On 24/09/2007, David Kastrup <dak@gnu.org> wrote:
> > >> Mike Hommey <mh@glandium.org> writes:
> > >>
> > >> > On Sun, Sep 23, 2007 at 10:42:08PM +0200, David Kastrup wrote:
> > >> >> -while case $# in 0) break ;; esac
> > >> >> +while test $# != 0
> > >> >
> > >> > Wouldn't -ne be better ?
> > >>
> > >> Why?
> > >
> > > Because -ne does a numeric comparison, != does a string comparison,
> > > and it's a numeric comparison happening, semantically speaking.
> > 
> > I don't see the point in converting $# and 0 into numbers before
> > comparing them.  "!=" is quite more readable, and the old code also
> > compared the strings.
> 
>   Fwiw $# already is a number. Hence test $# -ne 0 is definitely a
> better test.
> 
>   $# != 0 would yield sth like (strcmp(sprintf("%d", argc), "0"))
>   $# -ne 0 would yield sth like (argc != atoi("0")).

  Of course this holds only for shell where test/[ is a builtin, which
is the at least the case for zsh, bash, and dash (but not posh).

-- 
·O·  Pierre Habouzit
··O                                                madcoder@debian.org
OOO                                                http://www.madism.org