[ic] perl syntax of shopping cart items

[interchange-users@interchange.redhat.com (Honest to Goodness)]

I have a perl block on my checkout page and it needs to get the sku
codes of the items in the shopping cart. I can do a dump() and see them
buried deep down in some data structures. I've tried stuff like 

my @out = '';
my %stuff = '';
my $pop = '';
my @input = @{$Carts->{main}};

foreach %kip (@input) {
  foreach $pop (%stuff) {
    push (@out, $pop);
  }
}

and I get closer but I don't know what I'm doing so the going is kind of
slow. Does anyone know the perl syntax for getting at those code values?