my %params = $q->Vars;
my @keys = keys %params;
for my $k (sort @keys) {
    if (/[.]/) {
        my $v = delete $params{ $k };
        my $level = \%params;
        my @items = split /[.]/, $k;
        my $key = pop @items;
        for (@items) {
            $level->{ $_ } ||= {};
            $level = $level->{ $_ };
        };
        $level->{ $key } = $v;
    };
};