@fauton/cfg/dist/removeEmptyProduction.js

A package to work with context free grammars and LL1 parsers

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.removeEmptyProduction = void 0;
const populateCfg_1 = require("./utils/populateCfg");
const removeProductionRules_1 = require("./utils/removeProductionRules");
/**
 * 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
 */
function removeEmptyProduction(inputCfg) {
    const cfg = (0, populateCfg_1.populateCfg)(inputCfg);
    const { productionRules, variables } = cfg;
    // Filtering all the variables which dont have any production rules
    const emptyProductionVariables = variables.filter((variable) => productionRules[variable].length === 0);
    return (0, removeProductionRules_1.removeProductionRules)({
        productionRules,
        removedVariables: emptyProductionVariables,
        variables,
    });
}
exports.removeEmptyProduction = removeEmptyProduction;