import 'document/attributes.dart'; abstract class NotusEmbed { NotusAttribute get attribute; } class HorizontalRuleEmbed implements NotusEmbed { const HorizontalRuleEmbed(); @override NotusAttribute> get attribute => NotusAttribute.embed.horizontalRule; } class ImageEmbed implements NotusEmbed { const ImageEmbed(this.source) : assert(source != null); final String source; @override NotusAttribute get attribute => NotusAttribute.embed.image(source); }