use Scalar::Util;
{
  package Before;
  my %hUnwrapped;

  sub new {
    my ($sClass,$f) = @_;
    my $fBefore= sub {
      print "Special stuff for class $sClass\n";
      goto &$f
    };
    $hUnwrapped{Scalar::Util::refaddr($fBefore)}=$f;
    return bless($fBefore,$sClass);
  }

  sub i_know_what_im_doing {
    my $k = Scalar::Util::refaddr(shift);
    goto $hUnwrapped{$k};
  }
}

my $f1=Before->new(sub {print "Hello @_!\n";});
print "Wrapped sub\n-------------\n";
$f1->('tweedledum','tweedledee');

print "\nUnwrapped sub\n-------------\n";
$f1->i_know_what_im_doing('walrus','carpenter');