import { IContextFreeGrammarInput } from './types';
/**
 * Removes productions that has no rules and updates rules to remove those rules that references empty production variables
 * @param cfg Variables array and production rules record of cfg
 * @returns New production rules and variables without empty rule variables
 */
export declare function removeEmptyProduction(inputCfg: Pick<IContextFreeGrammarInput, 'variables' | 'productionRules'>): string[];