grammar.js

const Grammar = require('syntax-cli').Grammar;
const LLParsingTable = require('syntax-cli').LLParsingTable;
const jsdom = require("jsdom");

function getRulesFromDOM(window) {
    let rules = window.document.querySelectorAll("pre.grammar[id]");
    return [].map.call(rules, pre => pre.textContent);
}

const REGEXP = /(\s*:\n\s*)|\b(integer|float|identifier|string|whitespace|comment|other)\b|(\s*\n\s*)|(ε)/g;
function processRules(rules) {
    return rules.map(rule => {
        return  rule.trim().replace(REGEXP, m => {
            if (/^(integer|float|identifier|string|whitespace|comment|other)$/.test(m)) {
              return m.toUpperCase();
            }
            if (/:\n/.test(m)) { return "\n  : "; }
            if (/\n/.test(m)) { return "\n  | "; }
            if (/ε/.test(m)) { return "/* epsilon */"; }
        }) + "\n  ;";
    });
}

function toBNF(rules) {
    return "\n\n%%\n\n" + processRules(rules).join("\n");
}

var path_to_spec = "../index.html";
jsdom.env({
  file: path_to_spec,
  done: function (err, window) {
    let rules = getRulesFromDOM(window);
    let bnf = toBNF(rules);
    let data = Grammar.dataFromString(bnf, 'bnf')
    let grammar = Grammar.fromData(data, { mode: "LL1" });
    let table = new LLParsingTable({ grammar: grammar });
    table.getConflicts();
    console.log(table.hasConflicts());
  }
});