my @choices = @macro_args;
my %choices = map { $_ => 1 } @choices;

$self->add_hook ( 'validate_hook',

  sub {
    my ( $doc, $content ) = @_;
    # handle default -- we're allowed to set this enum to undefined if
    # there's a default value for this element
    if ( ! defined $content ) {
      if ( @{$self->elements('default')} ) {
        return;
      } else {
        die "attempt to set an enum to empty\n";
      }
    }
    if ( ! $choices{$content} ) {
      die "'$content' is not found in enum list\n";
    };
  }

);

$self->add_method ( 'enum_options', sub { return @choices } );