is_char_device: add sys., choose_method

Author: scivision

+stdlib/+sys/is_char_device.m

@@ -0,0 +1,8 @@
+function y = is_char_device(file)
+
+cmd = sprintf('test -c %s', file);
+
+[s, ~] = system(cmd);
+y = s == 0;
+
+end

+stdlib/is_char_device.m

@@ -3,27 +3,15 @@
 % e.g. NUL, /dev/null
 % false if file does not exist
 
-function ok = is_char_device(p)
+function ok = is_char_device(file, method)
 arguments
-  p {mustBeTextScalar}
+  file {mustBeTextScalar}
+  method (1,:) string = ["python", "sys"]
 end
 
-if stdlib.has_python()
-  ok = stdlib.python.is_char_device(p);
-elseif stdlib.isoctave()
-  [s, err] = stat(p);
-  ok = err == 0 && S_ISCHR(s.mode);
-else
-  ok = logical.empty;
-end
+fun = choose_method(method, "is_char_device");
+
+ok = fun(file);
 
 end
 
-%!assert (!is_exe(''))
-%!test
-%! if ispc
-%!   n = "NUL";
-%! else
-%!   n = "/dev/null";
-%! end
-%! assert (is_char_device(n))

+stdlib/private/choose_method.m

@@ -35,13 +35,20 @@
         if ~isunix(), continue, end
       end
 
-    case {"legacy", "sys"}, has = true;
+    case "legacy", has = true;
     case "native"
       has = stdlib.strempty(minVersion) || ~isMATLABReleaseOlderThan(minVersion);
 
       if endsWith(name, "create_symlink")
         if ~has || ispc(), continue, end
       end
+    case "sys"
+      has = true;
+
+      if endsWith(name, "is_char_device")
+        if ispc(), continue, end
+      end
+
     otherwise
       has = str2func("stdlib.has_" + m);
   end

test/TestExists.m

@@ -12,6 +12,7 @@
 % on CI matlabroot can be writable!
 fname = {'is_readable', 'is_writable'}
 method = {'java', 'native', 'legacy'}
+icm = {'python', 'sys'}
 end
 
 methods(TestClassSetup)
@@ -42,17 +43,24 @@ function test_is_rw(tc, Ps, method, fname)
 end
 
 
-function test_is_char_device(tc)
-is_capable(tc, @stdlib.python.is_char_device)
-
+function test_is_char_device(tc, icm)
 % /dev/stdin may not be available on CI systems
 if ispc
   n = "NUL";
 else
   n = "/dev/null";
 end
 
-tc.verifyTrue(stdlib.is_char_device(n))
+tc.assertNotEmpty(which("stdlib." + icm + ".is_char_device"))
+
+try
+  y = stdlib.is_char_device(n, icm);
+catch e
+  tc.verifyEqual(e.identifier, 'stdlib:choose_method:NameError', e.message)
+  return
+end
+
+tc.verifyTrue(y)
 end