> On 25 Oct 2016, at 05:40, Martijn Dekker <mart...@inlv.org> wrote:
>
> Op 25-10-16 om 00:42 schreef Stuart Shelton:
>> Failing this, is there any alternative to ‘typeset’ to list a
>> variable declared as local to a function but which has not yet been
>> assigned a value?
>
> Try simply testing the exit status of 'typeset -p' or 'declare -p'. If
> the variable is not declared, it exits unsuccessfully.
>
> if typeset -p "$var" >/dev/null 2>&1 && [[ ! -v $var ]]
> then ...
>
> As far as I can tell, this is not documented in 'help' or in the info
> page, by the way. Perhaps it should be.
>
> Also note that, while zsh and yash share this behaviour, ksh93 and
> mksh/pdksh do not. If you want to be compatible with all the shells that
> support 'typeset', you could do:
>
> if [ -n "$(typeset -p "$var" 2>/dev/null)" ] &&
> eval "[ -z \"\${var+s}\" ]"
> then ...
>
> which is slower because it uses a subshell.
>
> HTH,
>
> - M.
>
Hi Martijn,
Thanks for the suggestion!
However, it doesn’t appear to be able to detect local variables (is this
intentional or a bug?):
$ test() {
local testvar
echo “typeset test:"
typeset -p testvar && echo yes || echo no
echo “grep test:"
typeset -p | grep testvar
}
$ test
typeset test:
-bash: typeset: testvar: not found
no
grep test:
declare -- testvar
yes
Cheers,
Stuart
