Date: Mon, 15 Oct 2012 18:30:01 GMT From: Chris Rees <crees@FreeBSD.org> To: freebsd-rc@FreeBSD.org Subject: Re: docs/172692: [PATCH] Bring parts of the rc scripting guides up to date Message-ID: <201210151830.q9FIU11n045109@freefall.freebsd.org>
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The following reply was made to PR docs/172692; it has been noted by GNATS.
From: Chris Rees <crees@FreeBSD.org>
To: Michael Telahun Makonnen <mmakonnen@gmail.com>
Cc: freebsd-doc@freebsd.org, freebsd-rc@freebsd.org, freebsd-bugs@freebsd.org,
"bug-followup@freebsd.org" <bug-followup@freebsd.org>
Subject: Re: docs/172692: [PATCH] Bring parts of the rc scripting guides up to date
Date: Mon, 15 Oct 2012 19:26:22 +0100
On 15/10/2012, Michael Telahun Makonnen <mmakonnen@gmail.com> wrote:
> Some minor nits:
>
> - have the same prefix: <envar>${name}</envar>. For
> + have the same prefix: <envar>${name}_</envar>. For
>
> You should add the same correction to the very next sentence, which reads:
>
> Note: While it is possible to use a shorter name internally, e.g., just
Done, thanks!
>
>
> @@ -491,15 +491,6 @@
> our script will save us from possible
> collisions with the &man.rc.subr.8; namespace.</para>
>
> - <para>As long as an &man.rc.conf.5; variable and its
> - internal equivalent are the same, we can use a more
> - compact expression to set the default value:</para>
> -
> - <programlisting>: ${dummy_msg:="Nothing
> started."}</programlisting>
> -
> - <para>The current style is to use the more verbose form
> - though.</para>
> -
>
> Not sure why you felt this paragraph needed to be removed.
Because the style is clearer and makes it much more obvious when a
variable is having its own default value set. In ports at least, the
current style is to use the less verbose form.
> @@ -512,7 +503,11 @@
>
> <callout arearefs="rcng-confdummy-msg">
> <para>Here we use <envar>dummy_msg</envar> to actually
> - control our script, i.e., to emit a variable message.</para>
> + control our script, i.e., to emit a variable message.
> + Use of a shell function is overkill here, since it only
> + runs a single command; an equally valid alternative is:</para>
> +
> + <programlisting>start_cmd="echo \"$dummy_msg\""</programlisting>
>
> While you are technically correct, I think you misunderstood the
> writer's intent, which was to show how an rc.conf(8) variable can be
> used in a subroutine to control the behavior of the command. I agree
> that the example isn't a very good one (in that it doesn't depict a
> valid use case), but I think the "spirit" is correct. Maybe you can
> suggest a better example?
>
I think that this script is very simple by design, and making a better
example would complicate it. It is definitely worth pointing out the
alternative though; it makes useful food for thought; both examples
with a disclaimer.
Thank you very much for commenting, and I feel bad that I'm fobbing
you off. You've raised genuine points, but I had already considered
them. Please keep on at me if you think I still need to do something
about it.
Chris
[1] http://www.bayofrum.net/~crees/patches/rc-scripting-modernise2.diff
--
Chris Rees | FreeBSD Developer
crees@FreeBSD.org | http://people.freebsd.org/~crees
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