in reply to Re: use Data::DRef qw( :leaf );
in thread use Data::DRef qw( :leaf );

You can also use @EXPORT and @EXPORT_OK; @EXPORT exports what you assign to it every time, and @EXPORT_OK means it's ok to export something, but you have to specify it explicitly to import it.

Just look at the Exporter manpage, it's got all you ever wanted to know.