import { BNF } from "../core/BNF.js";
import { NonTerminal } from "../core/NonTerminal.js";
import { Sym } from "../core/Symbol.js";
import { Rule } from "./Rule.js";
export declare class Optional extends Rule {
    constructor(tgt: NonTerminal | undefined, child: Sym);
    getEntry(): Sym;
    createBNF(grammar: BNF): void;
}
//# sourceMappingURL=Optional.d.ts.map