our $storage; # or:
# our Storage $storage; # I think this works to type it
####
use Storage;
my $storage = new Storage();
use Source;
use Destination;
$Source::storage = $storage;
$Destination::storage = $storage;
my $input = 'source.txt';
while () {
$source = new Source($_);
$destination = new Destination();
$source->storeData();
$destination->useData();
}
##
##
use Storage;
my $storage = new Storage();
use Source;
use Destination;
my $input = 'source.txt';
while () {
$source = new Source($_, storage => $storage);
$destination = new Destination(storage => $storage);
$source->storeData();
$destination->useData();
}