Add classdef parsing for newer MATLAB versions

MATLAB's type function can natively read and display a *.mlapp's class
definition. This is a documented addition to R2016a, but has been tested
successfully in R2014b and newer. This allows us to skip the
intermediate zip file extraction and XML parsing. Though type does not
support an output argument, the output can be piped to a character array
using evalc and exported to an *.m file.

Resolves: #8

mlapp2classdef.m

@@ -145,9 +145,21 @@ function checkfile(pathname, filename, ext)
 
 
 function processapp(pathname, filename, appname, uielementflag)
-tmpdir = unpackapp(pathname, filename, appname);
-rawXML = loadXML(tmpdir);
-mymcode = stripXML(rawXML);
+isolderthanR2014b = verLessThan('matlab', '8.4');
+if isolderthanR2014b
+    % *.mlapp is a *.zip file, extract the contents and strip out the XML
+    % from the classdef
+    tmpdir = unpackapp(pathname, filename, appname);
+    rawXML = loadXML(tmpdir);
+    mymcode = stripXML(rawXML);
+    rmdir(tmpdir, 's');
+else
+    % Beginning with R2014b MATLAB's type function supports *.mlapp files,
+    % so we can pipe the output to an external file rather then extract
+    % from the *.zip file
+    evalcstr = sprintf('type(''%s'')', fullfile(pathname, filename));
+    mymcode = evalc(evalcstr);
+end
 
 if uielementflag.ReplaceAppUI
     % Convert App Designer UI elements to "regular" MATLAB UI elements
@@ -163,8 +175,7 @@ function processapp(pathname, filename, appname, uielementflag)
     end
 end
 
-writemfile(mymcode, pathname, appname);
-rmdir(tmpdir, 's');
+writemfile(mymcode, pathname, appname, isolderthanR2014b);
 disp(['Successfully converted ' filename '!']);
 end
 
@@ -211,12 +222,26 @@ function processapp(pathname, filename, appname, uielementflag)
 end
 
 
-function writemfile(mymcode, pathname, appname)
-% Write a cell array of strings to a *.m file.
-% Assumes each cell is a separate line.
+function writemfile(mymcode, pathname, appname, oldversionflag)
+% Write our m code to a file. Based on the MATLAB version used this will
+% either be in a cell array of strings (<R2014b) or a character array
+% (>=R2014b)
 fID = fopen(fullfile(pathname, sprintf('%s.m', appname)), 'w');
-for ii = 1:length(mymcode)
-    fprintf(fID, '%s\n', mymcode{ii});
+if oldversionflag
+    % MATLAB versions older than R2014b
+    % Write a cell array of strings to a *.m file
+    % Assumes each cell is a separate line
+    for ii = 1:length(mymcode)
+        fprintf(fID, '%s\n', mymcode{ii});
+    end
+else
+    % MATLAB versions R2014b and newer
+    % Write a character array to a *.m file
+    % Test for and strip out any leading whitespace characters
+    if isspace(mymcode(1))
+        mymcode(1) = [];
+    end
+    fprintf(fID, '%s', mymcode);
 end
 fclose(fID);
 end