import { Validator } from "./validator";
import { Order } from "./order";
import { Board, Unit } from "./types";
import * as Error from "./error";
export declare class RetreatValidator<Power> implements Validator<Power> {
    unitsRequiringOrder(board: Board<Power>): Set<Unit<Power>>;
    errorOfOrder(board: Board<Power>, order: Order<Power>): Error.InvalidPhase<{}> | Error.UnmovableLocation<any> | null;
    errorOfOrders(board: Board<Power>, orders: Set<Order<Power>>): Error.OrderNotExisted<Power> | null;
}