import { Unit, Board } from "./types";
import { Order } from "./order";
import { Error } from "./error";
export interface Validator<Power> {
    /**
     * @return The set of units that are requred orders.
     */
    unitsRequiringOrder(board: Board<Power>): Set<Unit<Power>>;
    /**
     * @return The error message of the order. If the order is valid, it's null.
     */
    errorOfOrder(board: Board<Power>, order: Order<Power>): Error | null;
    /**
     * @return The error message of the orders. If the set of the orders is valid, it's null.
     */
    errorOfOrders(board: Board<Power>, orders: Set<Order<Power>>): Error | null;
}