import { ApplySchemaAttributes, CommandFunction, KeyBindingProps, MarkExtension, MarkExtensionSpec, MarkSpecOverride, PrimitiveSelection } from '@remirror/core';
/**
 * Add underline formatting support to the editor.
 */
export declare class UnderlineExtension extends MarkExtension {
    get name(): "underline";
    createTags(): ("formattingMark" | "fontStyle")[];
    createMarkSpec(extra: ApplySchemaAttributes, override: MarkSpecOverride): MarkExtensionSpec;
    /**
     * Toggle the underline formatting of the selected text.
     *
     * This command is provided by the `UnderlineExtension`.
     */
    toggleUnderline(selection?: PrimitiveSelection): CommandFunction;
    /**
     * Attach the keyboard shortcut for formatting the text.
     */
    shortcut(props: KeyBindingProps): boolean;
}
declare global {
    namespace Remirror {
        interface AllExtensions {
            underline: UnderlineExtension;
        }
    }
}