Re: comment on RFE: 'shift'' [N] ARRAYNAME

[Dennis Williamson]

On Tue, Sep 25, 2018, 7:17 PM L A Walsh <bash@tlinx.org> wrote:

> It struck me as it might be convenient if 'shift' could take an optional
> arrayname as an argument.  Would that be possible or would it cause some
> incompatibility?
>
> i.e.
>
> >  set one two three four five
> >  dcl -a ARGV=("$@")
> >  shift ARGV
> >  echo "${ARGV[@]}"
> two three four five
> >  shift 2 ARGV
> four five
>
> I know it can be done with a function, but with more mess.
> I used (maybe there's a better way, but...):
>
> (in my lib file ArFuncs.shh, that I can include)
>
> [include stdalias]
> #[include Types] #if type-checking include Types+line below
> lshift () {
>   (($#)) || return 1
>   int nshift=1
>   if [[ $1 =~ ^[0-9]+$ ]]; then nshift=$1; shift;fi
>   #if ! isArr $1; then echo >&2 "Need arrayname"; return 1; fi
>   my ar=$1; shift
>   my h="$ar[@]"
>   set "${!h}"
>   shift $nshift
>   eval "${ar}=("$@")"
> }; export -f lshift
>
>
>
> "my" - What is this, Perl?

array_shift=2
arr=("${arr[@]:$array_shift}")

Done.


>