#autoload
__get_machines () {
        machinectl --full --no-legend --no-pager list |  {while read -r a b; do echo $a; done;};
}

local -a _machines
_machines=("${(fo)$(__get_machines)}")
typeset -U _machines
if [[ -n "$_machines" ]]; then
        _describe 'machines' _machines
else
        _message 'no machines'
fi