Function Parser

bench/input.js:444–525

(options, input, startPos)

}

var Parser = function Parser(options, input, startPos) {
  this.options = options = getOptions(options);
  this.sourceFile = options.sourceFile;
  this.keywords = keywordRegexp(keywords[options.ecmaVersion >= 6 ? 6 : 5]);
  var reserved = "";
  if (!options.allowReserved) {
    for (var v = options.ecmaVersion;; v--)
      { if (reserved = reservedWords[v]) { break } }
    if (options.sourceType == "module") { reserved += " await"; }
  }
  this.reservedWords = keywordRegexp(reserved);
  var reservedStrict = (reserved ? reserved + " " : "") + reservedWords.strict;
  this.reservedWordsStrict = keywordRegexp(reservedStrict);
  this.reservedWordsStrictBind = keywordRegexp(reservedStrict + " " + reservedWords.strictBind);
  this.input = String(input);

  // Used to signal to callers of `readWord1` whether the word
  // contained any escape sequences. This is needed because words with
  // escape sequences must not be interpreted as keywords.
  this.containsEsc = false;

  // Load plugins
  this.loadPlugins(options.plugins);

  // Set up token state

  // The current position of the tokenizer in the input.
  if (startPos) {
    this.pos = startPos;
    this.lineStart = this.input.lastIndexOf("\n", startPos - 1) + 1;
    this.curLine = this.input.slice(0, this.lineStart).split(lineBreak).length;
  } else {
    this.pos = this.lineStart = 0;
    this.curLine = 1;
  }

  // Properties of the current token:
  // Its type
  this.type = types.eof;
  // For tokens that include more information than their type, the value
  this.value = null;
  // Its start and end offset
  this.start = this.end = this.pos;
  // And, if locations are used, the {line, column} object
  // corresponding to those offsets
  this.startLoc = this.endLoc = this.curPosition();

  // Position information for the previous token
  this.lastTokEndLoc = this.lastTokStartLoc = null;
  this.lastTokStart = this.lastTokEnd = this.pos;

  // The context stack is used to superficially track syntactic
  // context to predict whether a regular expression is allowed in a
  // given position.
  this.context = this.initialContext();
  this.exprAllowed = true;

  // Figure out if it's a module code.