"use strict";

let GrammarError = require("../../grammar-error");
let asts = require("../asts");
let visitor = require("../visitor");

// Checks that all referenced rules exist.
function reportUndefinedRules(ast, options) {
  let check = visitor.build({
    rule_ref(node) {
      if (!asts.findRule(ast, node.name)) {
        throw new GrammarError(
          "Rule \"" + node.name + "\" is not defined.",
          node.location
        );
      }
    }
  });

  check(ast);

  if (options.allowedStartRules) {
    options.allowedStartRules.forEach(rule => {
      if (!asts.findRule(ast, rule)) {
        throw new GrammarError(
          "Start rule \"" + rule + "\" is not defined.");
      }
    });
  }
}

module.exports = reportUndefinedRules;