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'use strict';
// --------------------------------------------------------------------// Private Stuff// --------------------------------------------------------------------
// Helpers
const escapeStringFor = {};for (let c = 0; c < 128; c++) {  escapeStringFor[c] = String.fromCharCode(c);}escapeStringFor["'".charCodeAt(0)] = "\\'";escapeStringFor['"'.charCodeAt(0)] = '\\"';escapeStringFor['\\'.charCodeAt(0)] = '\\\\';escapeStringFor['\b'.charCodeAt(0)] = '\\b';escapeStringFor['\f'.charCodeAt(0)] = '\\f';escapeStringFor['\n'.charCodeAt(0)] = '\\n';escapeStringFor['\r'.charCodeAt(0)] = '\\r';escapeStringFor['\t'.charCodeAt(0)] = '\\t';escapeStringFor['\u000b'.charCodeAt(0)] = '\\v';
// --------------------------------------------------------------------// Exports// --------------------------------------------------------------------
exports.abstract = function(optMethodName) {  const methodName = optMethodName || '';  return function() {    throw new Error(        'this method ' +        methodName +        ' is abstract! ' +        '(it has no implementation in class ' +        this.constructor.name +        ')'    );  };};
exports.assert = function(cond, message) {  if (!cond) {    throw new Error(message || 'Assertion failed');  }};
// Define a lazily-computed, non-enumerable property named `propName`// on the object `obj`. `getterFn` will be called to compute the value the// first time the property is accessed.exports.defineLazyProperty = function(obj, propName, getterFn) {  let memo;  Object.defineProperty(obj, propName, {    get() {      if (!memo) {        memo = getterFn.call(this);      }      return memo;    },  });};
exports.clone = function(obj) {  if (obj) {    return Object.assign({}, obj);  }  return obj;};
exports.repeatFn = function(fn, n) {  const arr = [];  while (n-- > 0) {    arr.push(fn());  }  return arr;};
exports.repeatStr = function(str, n) {  return new Array(n + 1).join(str);};
exports.repeat = function(x, n) {  return exports.repeatFn(() => x, n);};
exports.getDuplicates = function(array) {  const duplicates = [];  for (let idx = 0; idx < array.length; idx++) {    const x = array[idx];    if (array.lastIndexOf(x) !== idx && duplicates.indexOf(x) < 0) {      duplicates.push(x);    }  }  return duplicates;};
exports.copyWithoutDuplicates = function(array) {  const noDuplicates = [];  array.forEach(entry => {    if (noDuplicates.indexOf(entry) < 0) {      noDuplicates.push(entry);    }  });  return noDuplicates;};
exports.isSyntactic = function(ruleName) {  const firstChar = ruleName[0];  return firstChar === firstChar.toUpperCase();};
exports.isLexical = function(ruleName) {  return !exports.isSyntactic(ruleName);};
exports.padLeft = function(str, len, optChar) {  const ch = optChar || ' ';  if (str.length < len) {    return exports.repeatStr(ch, len - str.length) + str;  }  return str;};
// StringBuffer
exports.StringBuffer = function() {  this.strings = [];};
exports.StringBuffer.prototype.append = function(str) {  this.strings.push(str);};
exports.StringBuffer.prototype.contents = function() {  return this.strings.join('');};
const escapeUnicode = str => String.fromCodePoint(parseInt(str, 16));
exports.unescapeCodePoint = function(s) {  if (s.charAt(0) === '\\') {    switch (s.charAt(1)) {      case 'b':        return '\b';      case 'f':        return '\f';      case 'n':        return '\n';      case 'r':        return '\r';      case 't':        return '\t';      case 'v':        return '\v';      case 'x':        return escapeUnicode(s.slice(2, 4));      case 'u':        return s.charAt(2) === '{' ?          escapeUnicode(s.slice(3, -1)) :          escapeUnicode(s.slice(2, 6));      default:        return s.charAt(1);    }  } else {    return s;  }};
// Helper for producing a description of an unknown object in a safe way.// Especially useful for error messages where an unexpected type of object was encountered.exports.unexpectedObjToString = function(obj) {  if (obj == null) {    return String(obj);  }  const baseToString = Object.prototype.toString.call(obj);  try {    let typeName;    if (obj.constructor && obj.constructor.name) {      typeName = obj.constructor.name;    } else if (baseToString.indexOf('[object ') === 0) {      typeName = baseToString.slice(8, -1); // Extract e.g. "Array" from "[object Array]".    } else {      typeName = typeof obj;    }    return typeName + ': ' + JSON.stringify(String(obj));  } catch (e) {    return baseToString;  }};