+sub _dispatch {
+ my ($required, $flags) = @_;
+
+ my $ref = ref($required);
+ if ($ref eq '') {
+ if ($required eq '*') {
+ return 0 unless ( $flags or ref( $flags ) );
+ } else {
+ return 0 unless ( $flags and (!ref( $flags ) || $flags->{$required} ));
+ }
+ } elsif ($ref eq 'HASH') {
+ foreach my $key (keys %{$required}) {
+ my $require = $required->{$key};
+ my $rflags = $flags->{$key};
+ return 0 unless _dispatch($require, $rflags);
+ }
+ } elsif ($ref eq 'ARRAY') {
+ my $satisfied = 0;
+ foreach my $require ( @{$required} ) {
+ my $rflags =
+ ( ref($flags) && !ref($require) && ( $require ne '*' ) )
+ ? $flags->{$require}
+ : $flags;
+ $satisfied++ if _dispatch( $require, $rflags );
+ }
+ return 0 unless $satisfied;
+ } else {
+ croak "Unexpected structure found: $ref";
+ }
+
+ return $flags;
+};
+