code: function ParseError(message, position) {
    this.name = 'ParseError';
    this.message = position
      ? message + ' at ' + position.source + ':' + position.start.line + ':' + position.start.column
      : message;
  }
docs: Create a parse error with source/line-number/col-number
  
  @param {String} message
  @param {Object} position