savejson & Matlab 2017a: Undefined function or variable 'st'.

[energynumbers]

Calls that formerly worked in Matlab 2016b and earlier, don't work in Matlab 2017a. From savejson I now get:

Undefined function or variable 'st'.
Error in savejson>matlabobject2json (line 448)
txt=struct2json(name,st,level,varargin{:});

[fangq]

@energynumbers, please check out my latest commit and let me know if that fixes the issue in the latest matlab.

[energynumbers]

Thanks, it now runs without error. However, it produces JSON which is inconsistent with what I had before - it's losing some data. I'll try to create a small example that reproduces the problem. More news shortly.

[energynumbers]

Looks to be some sort of confusion between a char array and a string array.

[energynumbers]

OK, the difference in behaviour between 2016b and 2017a is happening in loadjson.

Take this json file:

{
	"data": [
		[
			"a"
		],
		[
			"a\a"
		]
    ]
}

In 2016b, the resulting variable, after tst = loadjson(filename), has char arrays for tst.data{1}{1} and tst.data{2}{1}. And that happens whether or not there's a backslash in the second data item, in the json file.
In 2017a, the resulting variable has a string array for tst.data{1}{1}, and a char array for tst.data{2}{1}. If I remove the backslash from the second data item in the json file, then after loadjson, we're back to a char array for tst.data{1}{1}. That is, when I change the content of the second item, it changes the type of variable assigned to the first item. And this unpredictable behaviour between char arrays and strings, means that when I read in the json file, manipulate some of the elements, and then try to write it out, I'm trying to write out a cell array which contains a mix of strings and char arrays, and that doesn't go well - the whole cell array is written out as an array of blank elements.

[energynumbers]

Hmmm, maybe savejson is just writing out blanks for strings, more generally, too?

[energynumbers]

Ah, confirmed - savejson writes out blanks for strings:

a=struct()
a.b={string('hi')}
savejson('',a)

[energynumbers]

Going through savejson and changing the ischar tests to be ischar || isstring (likewise ~ischar && ~isstring) seems to fix this. I guess this probably applies to saveubjson too.

[Hell3000]

I am having the same problems.
Added the elseif with the matlab version check in savejson.m:
This might help:

function txt=obj2json(name,item,level,varargin)

if(iscell(item))
    txt=cell2json(name,item,level,varargin{:});
elseif(isstruct(item))
    txt=struct2json(name,item,level,varargin{:});
elseif(ischar(item))
    txt=str2json(name,item,level,varargin{:});
elseif ~verLessThan('matlab','9.1') && isstring(item)
    % versions 2016a and lower AND item is a string object 
    % (new string class since 2016b (9.1): isobject("String") returns true)
    
    % Don't know if this is correct in every case:
    % convert string to char by: item{:}
    txt=str2json(name,item{:},level,varargin{:});
elseif(isobject(item)) 
    txt=matlabobject2json(name,item,level,varargin{:});
else
    txt=mat2json(name,item,level,varargin{:});
end