more robustness across matlab versions

Author: scivision

+stdlib/canonical.m

@@ -22,7 +22,7 @@
   return
 end
 
-[s, r] = fileattrib(file);
+[s, r] = fileAttribCompatible(file);
 
 if s == 1
   c = r.Name;

+stdlib/get_permissions.m

@@ -16,7 +16,7 @@
 catch e
   switch e.identifier
     case 'MATLAB:UndefinedFunction'
-      perm = perm2char(stdlib.legacy.file_attributes(file));
+      perm = perm2char(file_attributes(file));
       b = 'legacy';
     case 'MATLAB:io:filesystem:filePermissions:CannotFindLocation'
       perm = '';

+stdlib/is_exe.m

@@ -16,7 +16,7 @@
   return
 end
 
-a = stdlib.legacy.file_attributes(file);
+a = file_attributes(file);
 
 if ~isempty(a)
   y = ~a.directory && (a.UserExecute || a.GroupExecute || a.OtherExecute);

+stdlib/is_readable.m

@@ -9,7 +9,7 @@
 
 function y = is_readable(file)
 
-a = stdlib.legacy.file_attributes(file);
+a = file_attributes(file);
 
 if isempty(a)
   y = false;

+stdlib/is_writable.m

@@ -9,7 +9,7 @@
 
 function y = is_writable(file)
 
-a = stdlib.legacy.file_attributes(file);
+a = file_attributes(file);
 
 if isempty(a)
   y = false;

+stdlib/perl_exe.m

@@ -12,13 +12,20 @@
 
 ps = [fileparts(mfilename("fullpath")), '/private/executable.pl'];
 
-[r, s] = perl(ps);
+exe = string.empty;
+
+try
+  [r, s] = perl(ps);
+catch e
+  if strcmp(e.identifier, 'MATLAB:perl:FileNotFound')
+    return
+  end
+  rethrow(e)
+end
 
 if s == 0 && isfile(r)
   exe = r;
   perle = r;
-else
-  exe = string.empty;
 end
 
 end

+stdlib/private/fileAttribCompatible.m

@@ -0,0 +1,15 @@
+%% FILEATTRIBCOMPATIBLE fileattrib required char until R2018a; this provides a seamless fallback
+
+function [s, r, id] = fileAttribCompatible(file)
+
+try
+  [s, r, id] = fileattrib(file);
+catch e
+  if strcmp(e.identifier, 'MATLAB:string')
+    [s, r, id] = fileattrib(char(file));
+  else
+    rethrow(e)
+  end
+end
+
+end