parent: native only

The overhead and complication of multiple backends was not worth the
possible 10% speedup in Python

Author: scivision

+stdlib/+java/parent.m

@@ -1,4 +1,7 @@
 function y = is_exe(p)
+arguments
+  p (1,1) string
+end
 
 y = isfile(p);
 

+stdlib/+native/parent.m

@@ -2,28 +2,26 @@
 %
 %% Inputs
 % * file: path to file or folder
-% * backend: backend to use
 %% Outputs
 % * par: parent directory of path
-% * b: backend used
 %% Examples:
 % stdlib.parent("a/b/c") == "a/b"
 % stdlib.parent("a/b/c/") == "a/b"
-%% Benchmark
-% Java or Python are each about 2-4x faster than native Matlab
 
-function [par, b] = parent(file, backend)
+function p = parent(file)
 arguments
   file string
-  backend (1,:) string = ["java", "python", "native"]
 end
 
-[fun, b] = hbackend(backend, "parent");
+p = fileparts(stdlib.drop_slash(file));
 
-if isscalar(file) || b == "native"
-  par = fun(file);
-else
-  par = arrayfun(fun, file);
+i = ~strlength(p);
+p(i) = ".";
+
+% the ~all(i) is for Windows Matlab < R2025a
+if ispc() && ~all(i)
+  i = p(~i) == stdlib.root_name(pth(~i));
+  p(i) = strcat(p(i), filesep);
 end
 
 end

+stdlib/+python/is_exe.m

@@ -0,0 +1,19 @@
+function par = parent(pth)
+arguments
+  pth (1,1) string
+end
+
+par = java.io.File(pth).getParent();
+if isempty(par)
+  par = ".";
+  if ispc()
+    rn = stdlib.root_name(pth);
+    if strlength(pth) && strlength(rn) && startsWith(pth, rn)
+      par = strcat(rn, filesep);
+    end
+  end
+else
+  par = string(par);
+end
+
+end

+stdlib/parent.m

@@ -1,4 +1,7 @@
 function par = parent(pth)
+arguments
+  pth (1,1) string
+end
 
 try
   op = py.pathlib.Path(pth);

example/+javafun/parent.m

@@ -1,7 +1,18 @@
-f = mfilename("fullpath") + ".m";
+function bench_parent()
 
-fno = @() stdlib.parent(f);
+in = mfilename("fullpath") + ".m";
+r = fileparts(fileparts(in));
+addpath(r)
+obj = onCleanup(@() rmpath(r));
 
-t_no = timeit(fno);
+h = @() stdlib.parent(in);
+fj = @() javafun.parent(in);
+fp = @() python.parent(in);
 
-disp("No Java: " + t_no + " s")
+tj = timeit(fj, 1) * 1e3;
+tp = timeit(fp, 1) * 1e3;
+th = timeit(h, 1) * 1e3;
+
+fprintf('Native: %f\nJava: %f\nPython: %f\n', th, tj, tp);
+
+end

+stdlib/+python/parent.m renamed to example/+python/parent.m

@@ -3,7 +3,6 @@
 
 properties (TestParameter)
 p = init_parent()
-backend = init_backend({'java', 'python', 'native'})
 end
 
 methods(TestClassSetup)
@@ -14,9 +13,9 @@ function test_dirs(tc)
 
 methods (Test, TestTags=["R2019b", "pure"])
 
-function test_parent(tc, p, backend)
-pr = stdlib.parent(p{1}, backend);
-tc.verifyEqual(pr, p{2}, sprintf("parent(%s, %s)", p{1}, backend))
+function test_parent(tc, p)
+pr = stdlib.parent(p{1});
+tc.verifyEqual(pr, p{2}, sprintf("parent(%s)", p{1}))
 end
 
 end
@@ -30,7 +29,7 @@ function test_parent_array(tc)
 in =  ["",  ".", "..", "../..", "a/", "a/b", "ab/.parent", "ab/.parent.txt", "a/b/../.parent.txt"];
 exp = [".", ".", ".", "..",     ".",  "a",   "ab",         "ab",             fullfile("a", "b", "..")];
 
-out = stdlib.parent(in, 'native');
+out = stdlib.parent(in);
 tc.verifyEqual(out, exp)
 end