parent: handle Windows root paths

Author: scivision

+stdlib/parent.m

@@ -12,6 +12,12 @@
 else
   % drop duplicated slashes in the parent path
   p = regexprep(p, "//+", "/");
+
+  if ispc && any(strlength(p) == [2,3]) && isletter(extractBetween(p, 1, 1) && extractBetween(p, 2, 2) == ":")
+    % 2 or 3 char drive letter
+    p = stdlib.root(p);
+    return
+  end
   % have to drop_slash on input to get expected parent path
   p = strip(stdlib.posix(p), "right", "/");
   j = strfind(p, "/");

test/TestFilePure.m

@@ -17,8 +17,8 @@
 sub_is_subdir
 ref_is_subdir
 
-in_parent = {"", ".", "..", "../..", "a/", "a/b", "a/b/", "ab/.parent", "ab/.parent.txt", "a/b/../.parent.txt", "a/////b////c"}
-ref_parent = {".", ".", ".", "..",   ".",  "a",   "a",    "ab",         "ab",             "a/b/..",             "a/b"}
+in_parent
+ref_parent
 
 in_suffix = {"", "/foo/bar/baz", "/foo/bar/baz/", "foo/bar/baz.txt", "foo/bar/baz.txt.gz", ".stat", ".stat.txt"}
 ref_suffix = {"", "", "", ".txt", ".gz", ".stat", ".txt"}
@@ -37,11 +37,14 @@
 end
 
 methods (TestParameterDefinition, Static)
-function [base_relative_to, other_relative_to, ref_relative_to, ref_proximate_to, in_root, ref_root] = init_relative_to(classToTest) %#ok<INUSD>
+function [base_relative_to, other_relative_to, ref_relative_to, ref_proximate_to, in_root, ref_root, in_parent, ref_parent] = init_relative_to(classToTest) %#ok<INUSD>
 
 in_root = {"", "a/b", "./a/b", "../a/b", "/etc", "c:/etc"};
 ref_root = {"", "", "", "", "/", ""};
 
+in_parent = {"", ".", "..", "../..", "a/", "a/b", "a/b/", "ab/.parent", "ab/.parent.txt", "a/b/../.parent.txt", "a/////b////c", "c:/", "c:\", "c:/a/b", "c:\a/b"};
+ref_parent = {".", ".", ".", "..",   ".",  "a",   "a",    "ab",         "ab",             "a/b/..",             "a/b",          ".",    ".",    "c:/a",     "c:\a"};
+
 if ispc
 
 base_relative_to = {'', 'Hello', 'Hello', ...
@@ -55,6 +58,11 @@
 ref_proximate_to = ref_relative_to;
 ref_proximate_to{end} = other_relative_to{end};
 
+ref_root{12} = "c:/";
+ref_root{13} = "c:/";
+ref_root{14} = "c:/a";
+ref_root{15} = "c:/a";
+
 ref_root{5} = "";
 ref_root{6} = "c:/";