import { type StaticParser } from './static';
import { type IParser, type IProperties, type IMapping } from './parser';
export type StaticOptional<Parser extends IParser, Result extends unknown = [StaticParser<Parser>] | []> = (Result);
export interface IOptional<Output extends unknown = unknown> extends IParser<Output> {
    type: 'Optional';
    parser: IParser;
}
export declare function Optional<Parser extends IParser, Mapping extends IMapping = IMapping<StaticOptional<Parser>>>(parser: Parser, mapping: Mapping): IOptional<ReturnType<Mapping>>;
export declare function Optional<Parser extends IParser>(parser: Parser): IOptional<StaticOptional<Parser>>;
export declare function IsOptional(value: unknown): value is IOptional;
export declare function ParseOptional<Context extends IProperties, Parser extends IParser>(context: Context, parser: Parser, input: string): [] | [[unknown] | [], unknown];