+=head2 _tag
+
+Get value of tag. Tag name is case insensitive (don't ask why),
+we ignore namespaces and can take optional C<sub_key>
+(usually C<_content>).
+
+ _tag( $tag_hash, $name, $sub_key )
+
+=cut
+
+sub _tag {
+ my ( $tag_hash, $name, $sub_key ) = @_;
+ confess "need hash as first argument" unless ( ref $tag_hash eq 'HASH' );
+ $name = (grep { m/^(?:\w+:)*$name$/i } keys %$tag_hash )[0];
+# $name =~ s/^\w+://;
+ if ( defined $tag_hash->{$name} ) {
+ if ( ! defined $sub_key ) {
+ return $tag_hash->{$name};
+ } elsif ( defined $tag_hash->{$name}->{$sub_key} ) {
+ return $tag_hash->{$name}->{$sub_key};
+ } else {
+ return if ( $name =~ m/^value$/i );
+ warn "can't find '$name/$sub_key' in ", dump( $tag_hash );
+ return;
+ }
+ } else {
+ warn "can't find '$name' in ", dump( $tag_hash );
+ return;
+ }
+}
+