code: function(token){
                  throw new SyntaxError("Unexpected token '" + token.value + "' at line " + token.startLine + ", col " + token.startCol + ".", token.startLine, token.startCol);
              }
docs: Throws an error when an unexpected token is found.
  @param {Object} token The token that was found.
  @method _unexpectedToken
  @return {void}
  @private