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_txtdesc2cfg.m
    path of file: ./repos/spm12/matlabbatch
    
    the code of the file until where you have to start completion: function cfg = cfg_txtdesc2cfg(fname)

% Create a cfg_item tree from a short-hand text description
% cfg = cfg_txtdesc2cfg(fname)
% This utility reads a text file from fname and creates a configuration
% object tree according to the following grammar rules.
% 
% Each line in the file has the form
%
%  TAGNAME = RIGHTHANDSIDE
%
% where TAGNAME is a valid tag name for a cfg_item object. For each line, a
% cfg_item object with tag TAGNAME will be created. Its class is determined
% by the format of RIGHTHANDSIDE. RIGHTHANDSIDE can be one of
% 
%  (TAGNAME_1 TAGNAME_2 ... TAGNAME_N) - cfg_branch
%
%  {TAGNAME_1 TAGNAME_2 ... TAGNAME_N} - cfg_repeat
%
%  [TAGNAME_1 TAGNAME_2 ... TAGNAME_N] - cfg_mchoice
%
%  |TAGNAME_1 TAGNAME_2 ... TAGNAME_N| - cfg_choice
%
% with .val (for cfg_branch) or .values (all other cases) fields set to the
% cfg_item objects referenced by TAGNAME_1 ... TAGNAME_N.
%
%  TAGNAME_1 - same type as TAGNAME_1, but with tag TAGNAME instead of
%              TAGNAME_1
%
%  'some_matlab_code' - this MATLAB code will be evaluated. Its return
%                       value should be a cfg_* object. The tag of this
%                       object will be set to 'TAGNAME'
%
% The cfg_item object returned will be the one defined in the first line of
% the file. The depth of the substitutions is not limited, but all
% substitutions must finally be resolvable to 'some_matlab_code'.
%
% A valid description would be
%
%  toplevel = {mychoice mybranch}
%  mychoice = |myrepeat myconst|
%  myrepeat = {mymenu}
%  mybranch = (mymchoice myentry)
%  mymchoice = [myfiles myfiles1]
%  myfiles1 = myfiles
%  myfiles  = 'cfg_files'
%  myconst  = 'cfg_const'
%  myentry  = 'cfg_entry'

    
function cfg = cfg_txtdesc2cfg(fname)

% Create a cfg_item tree from a short-hand text description
% cfg = cfg_txtdesc2cfg(fname)
% This utility reads a text file from fname and creates a configuration
% object tree according to the following grammar rules.
% 
% Each line in the file has the form
%
%  TAGNAME = RIGHTHANDSIDE
%
% where TAGNAME is a valid tag name for a cfg_item object. For each line, a
% cfg_item object with tag TAGNAME will be created. Its class is determined
% by the format of RIGHTHANDSIDE. RIGHTHANDSIDE can be one of
% 
%  (TAGNAME_1 TAGNAME_2 ... TAGNAME_N) - cfg_branch
%
%  {TAGNAME_1 TAGNAME_2 ... TAGNAME_N} - cfg_repeat
%
%  [TAGNAME_1 TAGNAME_2 ... TAGNAME_N] - cfg_mchoice
%
%  |TAGNAME_1 TAGNAME_2 ... TAGNAME_N| - cfg_choice
%
% with .val (for cfg_branch) or .values (all other cases) fields set to the
% cfg_item objects referenced by TAGNAME_1 ... TAGNAME_N.
%
%  TAGNAME_1 - same type as TAGNAME_1, but with tag TAGNAME instead of
%              TAGNAME_1
%
%  'some_matlab_code' - this MATLAB code will be evaluated. Its return
%                       value should be a cfg_* object. The tag of this
%                       object will be set to 'TAGNAME'
%
% The cfg_item object returned will be the one defined in the first line of
% the file. The depth of the substitutions is not limited, but all
% substitutions must finally be resolvable to 'some_matlab_code'.
%
% A valid description would be
%
%  toplevel = {mychoice mybranch}
%  mychoice = |myrepeat myconst|
%  myrepeat = {mymenu}
%  mybranch = (mymchoice myentry)
%  mymchoice = [myfiles myfiles1]
%  myfiles1 = myfiles
%  myfiles  = 'cfg_files'
%  myconst  = 'cfg_const'
%  myentry  = 'cfg_entry'
%  mymenu   = 'cfg_menu'
%
% The resulting object tree will need further adjustment, but it can serve
% as a good starting point for modifying program code. The sequence
%
%  cfg = cfg_txtdesc2cfg('mygrammar.txt');
%  cfgstr = gencode(cfg);
%  cfgchr = sprintf('%s\n',cfgstr{:});
%  clipboard('copy', cfgchr)
%
% will create a cfg_item tree as defined in 'mygrammar.txt', convert it
% into MATLAB code lines, print them into a newline-separated string and
% copy this string into the clipboard. From there, it can be pasted into
% any application (MATLAB editor, external editor ...) where it can be
% processed further.
%
% 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_txtdesc2cfg.m 4867 2012-08-30 13:04:51Z volkmar $

rev = '$Rev: 4867 $'; 


% Read file
fid = fopen(fname, 'r');
s = textscan(fid,'%s','Delimiter','\n');

% Parse lines into left/right values, separated by equal signs and
% surronding space characters
pat = '^\s*(?<left>\w+)\s*=\s*(?<right>.+)$';
lr  = regexp(s{1}, pat, 'names');
fail = cellfun(@isempty, lr);
if any(fail)
    fprintf('The following lines could not be parsed into left/right pairs:\n')
    ifail = find(fail);
    for k = 1:numel(ifail)
        fprintf('%0*d: %s\n', floor(log10(max(ifail)))+1, ifail(k), s{1}{k});
    end