Warning: I am not TheDamian, nor lwall.

As to the parameter list on the sub import(...) { line, that's from RFC 128 (nice number, no?), with some Larifications. ($pkg : ARRAY $export=undef, ARRAY $ok=undef, HASH $tags=undef) gets a bit confusing. I read it like this. First, we've got $pkg, which is untyped. I think the : is a typo for ;, meaning "end of required parameters". Then follows $export, an arrayref which defaults to being undef, $ok, another arrayref with the same default, and $tags, a hash that still defaults to undef. If I'm worng, and that : really is a :, then that means that $pkg does indeed have three attributes... but those would be parameter list attributes, and we know what all of those are, and they don't look like that. Perhaps with Larry's adverbial :, those are suposted to be definitions of adverbial variables.

Next, we've got my $from_pkg=caller.package;, and you're wondering if that's an attribute of the value that caller returns, or if it's a method on the object that it returns. Well, it doesn't really matter is the answer. An attribute looks an awful lot like a method call. In this case, it's probably an attribute, but the difference in calling convention is nil. An attribute is essentily an lvalueable sub that you never had to write, or a hashref that's magicly a part of a value.

OK, time for me to catch my bus. I'll proabably finish this later.