package MyExporter;

use Exporter ();

BEGIN { our @ISA = 'Exporter'; }

sub import {
   our @EXPORT_OK;
   our @EXPORT_TAGS;

  #my $pkg = \%::;
  #$pkg = $pkg->{$_} foreach ((caller().'::') =~ /\G(.*::)/g);

   my $pkg = caller() . '::';
   { no strict 'refs'; $pkg = *$pkg; }

   local *EXPORT_OK   = $pkg->{'EXPORT_OK'};
   local *EXPORT_TAGS = $pkg->{'EXPORT_TAGS'};

   {  # Expand tag names into referenced name sets
      my %seen;    
      $EXPORT_TAGS{all} = [ 
         grep { !$seen{$_}++ } 
            map { m/^:(.*)$/ ? @{$EXPORT_TAGS{$1}} : $_ } 
               @{$EXPORT_TAGS{all}} 
      ];
   }

   {  # Add tag set names not already listed into @EXPORT_OK
      my %seen;    
      $seen{$_}++ foreach @EXPORT_OK;
      push @EXPORT_OK,
        grep { !$seen{$_}++ } 
           @{$EXPORT_TAGS{$_}}
              foreach keys %EXPORT_TAGS;
    }

    &Exporter::import;
}