"Jeff Hostetler via GitGitGadget" <gitgitgadget@xxxxxxxxx> writes:
> From: Jeff Hostetler <jeffhost@xxxxxxxxxxxxx>
>
> Signed-off-by: Jeff Hostetler <jeffhost@xxxxxxxxxxxxx>
> Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx>
I hadn't signed off on this one yet ;-)
> +is_value () {
> + test -n "$1" && test "${1::1}" != "-"
> +}
${var:ofs:len} is a bash-ism. If you run this test under /bin/dash
instead of /bin/dash, you'll likely see it fail.
If it were a good idea to see if $1 begins with a dash, a more
natural (to shell programmers) way to do so is
case "$1" in -*) false ;; ?*) true ;; *) false ;; esac
but given how this is used below, we do not want to special case
dash.
There isn't anything wrong in "mkdir ./-foo && start_daemon -C -foo"
in other words.
> +start_daemon () {
> + r= &&
> + tf= &&
> + t2= &&
> + tk= &&
FYI, you can write these on a single line, i.e.
r= tf= t2= tk= &&
Spending lines and spaces for the meat of the script would enhance
readability but for things like a boilerplate "we clear variables
before using them", being concise may be less distracting.
> + while test "$#" -ne 0
> + do
> + case "$1" in
> + -C)
> + shift;
> + is_value $1 || BUG "error: -C requires value"
> + r="-C $1"
> + shift
> + ;;
> + ...
> + esac
> + done &&
A more natural way to write these loops is
while ...
do
case "$1" in
-C)
r="-C ${2?}"
shift
;;
... all other options you handle ...
-*)
echo >&2 "unknown option $1"
exit 1
;;
*)
break
;;
esac
shift
done
i.e. shifting out what we just saw is the default and happens
immediately after the case/esac, and extra shift after consuming
an option parameter happens in each case arm.
An acceptable slight variation is
-C)
shift
r="-C ${1?}"
;;
but the first form is more logical and clear, i.e. "when we see '-C',
we want two on the command line, -C itself and the parameter it takes"
is conveyed more strongly with "${2?}" there.
For an additional bonus, we could also accept the stuck form, i.e.
case "$1" in
-C)
r="-C ${2?}"
shift
;;
-C*)
r="-C {$1#-C}"
;;
...
