add root()

Author: scivision

+stdlib/root.m

@@ -0,0 +1,23 @@
+function r = root(p, use_java)
+arguments
+  p (1,1) string
+  use_java (1,1) logical = false
+end
+
+if use_java
+  r = string(java.io.File(p).toPath().getRoot());
+else
+  if ispc
+    if strlength(p) >= 2 && isletter(extractBetween(p, 1, 1)) && extractBetween(p, 2, 2) == ":"
+      r = extractBetween(p, 1, 2) + "/";
+    else
+      r = "";
+    end
+  elseif startsWith(p, "/")
+    r = "/";
+  else
+    r = "";
+  end
+end
+
+end

test/TestFilePure.m

@@ -27,14 +27,20 @@
     "a/b/../../c/../..", "a////b"}
 ref_norm = {".", "a/b", "c", "a/c", "c", ".", ...
     "..", "a/b"}
+
+in_root
+ref_root
 end
 
 properties
 tobj
 end
 
 methods (TestParameterDefinition, Static)
-function [base_relative_to, other_relative_to, ref_relative_to, ref_proximate_to] = init_relative_to(classToTest) %#ok<INUSD>
+function [base_relative_to, other_relative_to, ref_relative_to, ref_proximate_to, in_root, ref_root] = init_relative_to(classToTest) %#ok<INUSD>
+
+in_root = {"", "a/b", "./a/b", "../a/b", "/etc", "c:/etc"};
+ref_root = {"", "", "", "", "/", ""};
 
 if ispc
 
@@ -49,6 +55,8 @@
 ref_proximate_to = ref_relative_to;
 ref_proximate_to{end} = other_relative_to{end};
 
+ref_root{end} = "c:/";
+
 else
 
 base_relative_to = {'', '',  '/', '/', 'Hello', 'Hello',  '/dev/null', '/a/b', 'c', ...
@@ -191,6 +199,13 @@ function test_normalize(tc, in_norm, ref_norm)
 end
 
 
+function test_root(tc, in_root, ref_root)
+
+tc.verifyEqual(stdlib.root(in_root), ref_root)
+
+end
+
+
 function test_with_suffix(tc)
 
 tc.verifyEqual(stdlib.with_suffix("", ""), "")