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

From: Junio C Hamano <gitster@pobox.com>
Date: Sep 23, 2007, 22:20 UTC
Message-ID: <7vhcllc9bz.fsf@gitster.siamese.dyndns.org>
In-Reply-To: <85myvdktb3.fsf@lola.goethe.zz>

David Kastrup <dak@gnu.org> writes:

Show 22 quoted lines

> A lot of shell scripts contained stuff starting with
>
> 	while case "$#" in 0) break ;; esac
>
> and similar.  I consider breaking out of the condition instead of the
> body od the loop ugly, and the implied "true" value of the
> non-matching case is not really obvious to humans at first glance.  It
> happens not to be obvious to some BSD shells, either, but that's
> because they are not POSIX-compliant.  In most cases, this has been
> replaced by a straight condition using "test".  "case" has the
> advantage of being faster than "test" on vintage shells where "test"
> is not a builtin.  Since none of them is likely to run the git
> scripts, anyway, the added readability should be worth the change.
>
> A few loops have had their termination condition expressed
> differently.
>
> Signed-off-by: David Kastrup <dak@gnu.org>
> ---
>
> Ok, this is not really what we have been talking about except in one
> case, but I think it is actually more of an improvement.

Gaah, didn't I say I do NOT think it is an improvement?

> I consider breaking out of the condition instead of the
> body od the loop ugly,

Well, as we all know that we disagree on this point, stating what you consider one-sidedly here is quite inappropriate.

> and the implied "true" value of the
> non-matching case is not really obvious to humans at first
> glance.

It is more like "if you do not know shell".

In other words, I am somewhat disgusted with the first part of your proposed commit log message, although I like what the patch does ;-).

Show 5 quoted lines

> -while case "$#" in 0) break ;; esac
> +while test "$#" != 0
>  do
>      case "$1" in
>      -a)

And let's not quote "$#".