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: savejson.m
    path of file: ./repos/Coursera-Machine-Learning-Stanford/Week 2/Programming Assignment/machine-learning-ex1/ex1/lib/jsonlab
    
    the code of the file until where you have to start completion: function json=savejson(rootname,obj,varargin)
%
% json=savejson(rootname,obj,filename)
%    or
% json=savejson(rootname,obj,opt)
% json=savejson(rootname,obj,'param1',value1,'param2',value2,...)
%
% convert a MATLAB object (cell, struct or array) into a JSON (JavaScript
% Object Notation) string
%
% author: Qianqian Fang (fangq<at> nmr.mgh.harvard.edu)
% created on 2011/09/09
%
% $Id: savejson.m 460 2015-01-03 00:30:45Z fangq $
%
% input:
%      rootname: the name of the root-object, when set to '', the root name
%        is ignored, however, when opt.ForceRootName is set to 1 (see below),
%        the MATLAB variable name will be used as the root name.
%      obj: a MATLAB object (array, cell, cell array, struct, struct array).
%      filename: a string for the file name to save the output JSON data.
%      opt: a struct for additional options, ignore to use default values.
%        opt can have the following fields (first in [.|.] is the default)

    
function json=savejson(rootname,obj,varargin)
%
% json=savejson(rootname,obj,filename)
%    or
% json=savejson(rootname,obj,opt)
% json=savejson(rootname,obj,'param1',value1,'param2',value2,...)
%
% convert a MATLAB object (cell, struct or array) into a JSON (JavaScript
% Object Notation) string
%
% author: Qianqian Fang (fangq<at> nmr.mgh.harvard.edu)
% created on 2011/09/09
%
% $Id: savejson.m 460 2015-01-03 00:30:45Z fangq $
%
% input:
%      rootname: the name of the root-object, when set to '', the root name
%        is ignored, however, when opt.ForceRootName is set to 1 (see below),
%        the MATLAB variable name will be used as the root name.
%      obj: a MATLAB object (array, cell, cell array, struct, struct array).
%      filename: a string for the file name to save the output JSON data.
%      opt: a struct for additional options, ignore to use default values.
%        opt can have the following fields (first in [.|.] is the default)
%
%        opt.FileName [''|string]: a file name to save the output JSON data
%        opt.FloatFormat ['%.10g'|string]: format to show each numeric element
%                         of a 1D/2D array;
%        opt.ArrayIndent [1|0]: if 1, output explicit data array with
%                         precedent indentation; if 0, no indentation
%        opt.ArrayToStruct[0|1]: when set to 0, savejson outputs 1D/2D
%                         array in JSON array format; if sets to 1, an
%                         array will be shown as a struct with fields
%                         "_ArrayType_", "_ArraySize_" and "_ArrayData_"; for
%                         sparse arrays, the non-zero elements will be
%                         saved to _ArrayData_ field in triplet-format i.e.
%                         (ix,iy,val) and "_ArrayIsSparse_" will be added
%                         with a value of 1; for a complex array, the 
%                         _ArrayData_ array will include two columns 
%                         (4 for sparse) to record the real and imaginary 
%                         parts, and also "_ArrayIsComplex_":1 is added. 
%        opt.ParseLogical [0|1]: if this is set to 1, logical array elem
%                         will use true/false rather than 1/0.
%        opt.NoRowBracket [1|0]: if this is set to 1, arrays with a single
%                         numerical element will be shown without a square
%                         bracket, unless it is the root object; if 0, square
%                         brackets are forced for any numerical arrays.
%        opt.ForceRootName [0|1]: when set to 1 and rootname is empty, savejson
%                         will use the name of the passed obj variable as the 
%                         root object name; if obj is an expression and 
%                         does not have a name, 'root' will be used; if this 
%                         is set to 0 and rootname is empty, the root level 
%                         will be merged down to the lower level.
%        opt.Inf ['"$1_Inf_"'|string]: a customized regular expression pattern
%                         to represent +/-Inf. The matched pattern is '([-+]*)Inf'
%                         and $1 represents the sign. For those who want to use
%                         1e999 to represent Inf, they can set opt.Inf to '$11e999'
%        opt.NaN ['"_NaN_"'|string]: a customized regular expression pattern
%                         to represent NaN
%        opt.JSONP [''|string]: to generate a JSONP output (JSON with padding),
%                         for example, if opt.JSONP='foo', the JSON data is
%                         wrapped inside a function call as 'foo(...);'
%        opt.UnpackHex [1|0]: conver the 0x[hex code] output by loadjson 
%                         back to the string form
%        opt.SaveBinary [0|1]: 1 - save the JSON file in binary mode; 0 - text mode.
%        opt.Compact [0|1]: 1- out compact JSON format (remove all newlines and tabs)
%
%        opt can be replaced by a list of ('param',value) pairs. The param 
%        string is equivallent to a field in opt and is case sensitive.
% output:
%      json: a string in the JSON format (see http://json.org)
%
% examples:
%      jsonmesh=struct('MeshNode',[0 0 0;1 0 0;0 1 0;1 1 0;0 0 1;1 0 1;0 1 1;1 1 1],... 
%               'MeshTetra',[1 2 4 8;1 3 4 8;1 2 6 8;1 5 6 8;1 5 7 8;1 3 7 8],...
%               'MeshTri',[1 2 4;1 2 6;1 3 4;1 3 7;1 5 6;1 5 7;...
%                          2 8 4;2 8 6;3 8 4;3 8 7;5 8 6;5 8 7],...
%               'MeshCreator','FangQ','MeshTitle','T6 Cube',...
%               'SpecialData',[nan, inf, -inf]);
%      savejson('jmesh',jsonmesh)
%      savejson('',jsonmesh,'ArrayIndent',0,'FloatFormat','\t%.5g')
%
% license:
%     BSD, see LICENSE_BSD.txt files for details
%
% -- this function is part of JSONLab toolbox (http://iso2mesh.sf.net/cgi-bin/index.cgi?jsonlab)
%

if(nargin==1)
   varname=inputname(1);
   obj=rootname;
   if(isempty(varname)) 
      varname='root';
   end