foreach my $i ($ref->@a) {
    print $i;           # I want to see the content of the array, this
+ gave me an error.
}
[download]

I can't tell if this is what you mean or not:

foreach my $i ( @{$ref}{@a} ) {
    print $i;
}
[download]

Or maybe it's simpler than that:

foreach my $i ( @a ) {
    print $i;
}
[download]