feat: recursive example

setup.py

@@ -102,10 +102,10 @@ def bazel_build(self, ext: BazelExtension) -> None:
                     should_copy = True
 
                 if should_copy:
-                    new_directory = libdir / os.path.relpath(root, srcdir)
-                    if not os.path.exists(new_directory):
-                        os.mkdir(new_directory)
-                    shutil.copyfile(root / fp, libdir / new_directory / fp)
+                    dstdir = libdir / os.path.relpath(root, srcdir)
+                    if not os.path.exists(dstdir):
+                        os.mkdir(dstdir)
+                    shutil.copyfile(root / fp, dstdir / fp)
 
 
 setuptools.setup(

src/BUILD

@@ -6,7 +6,7 @@ load(
 
 py_library(
     name = "nanobind_example",
-    srcs = ["nanobind_example/__init__.py"],
+    srcs = ["nanobind_example/__init__.py", "nanobind_example/sub_ext/__init__.py"],
     data = [":nanobind_example_ext"],
     visibility = ["//visibility:public"],
 )
@@ -20,4 +20,6 @@ nanobind_stubgen(
     name = "nanobind_example_ext_stubgen",
     module = ":nanobind_example_ext",
     marker_file = "src/py.typed",
+    output_directory = "src",
+    recursive = True,
 )

src/nanobind_example/sub_ext/__init__.py

@@ -0,0 +1 @@
+from ..nanobind_example_ext.sub_ext import sub

src/nanobind_example_ext.cpp

@@ -7,4 +7,8 @@ using namespace nb::literals;
 NB_MODULE(nanobind_example_ext, m) {
     m.doc() = "This is a \"hello world\" example with nanobind";
     m.def("add", [](int a, int b) { return a + b; }, "a"_a, "b"_a);
+
+    nb::module_ sm = m.def_submodule("sub_ext", "A submodule of 'nanobind_example_ext'");
+
+    sm.def("sub", [](int a, int b) { return a - b; }, "a"_a, "b"_a);
 }