Select Code to Download

use constant PUBLIC => 0, PRIVATE => 1;
%query = (
...

my @public_actions =
  grep $query{$_}->{visibility} == PUBLIC, keys %query;

sub register_action {
  my( $action, $subname ) = @_;
...
  $query{ $action } = { visibility => ($subname =~ /^_/),
                        code => \&{$subname} };
}