You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: cfg_ui_util.m
    path of file: ./repos/bspm/thirdparty/spm12/matlabbatch
    
    the code of the file until where you have to start completion: function varargout = cfg_ui_util(cmd, varargin)
%CFG_UI_UTIL utility functions for displaying job, module and item values
% This function is a collection of utility functions to display a job,
% module or data summary. It also handles all value display and editing for
% a particular item.
%
% This code is part of a batch job configuration system for MATLAB. See 
%      help matlabbatch

    
function varargout = cfg_ui_util(cmd, varargin)
%CFG_UI_UTIL utility functions for displaying job, module and item values
% This function is a collection of utility functions to display a job,
% module or data summary. It also handles all value display and editing for
% a particular item.
%
% This code is part of a batch job configuration system for MATLAB. See 
%      help matlabbatch
% for a general overview.
%_______________________________________________________________________
% Copyright (C) 2007 Freiburg Brain Imaging

% Volkmar Glauche
% $Id: cfg_ui_util.m 6136 2014-08-07 10:35:12Z volkmar $

rev = '$Rev: 6136 $';  %#ok<NASGU>

switch lower(cmd)
    case {'preview'}
        % cfg_ui_util('preview', ciid, dflag)
        [ciid, dflag] = deal(varargin{1:2});
        contents = cfg_ui_util('showitem', ciid, dflag);
        [tag, val] = cfg_util('harvest', ciid{:});
        try
            feval(contents{10}, val);
        end