Replace pybind11 with nanobind at the C++ module file

frontend/catalyst/third_party/oqc/src/oqc_python_module.cpp

@@ -12,9 +12,12 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#include <pybind11/eval.h>
-#include <pybind11/pybind11.h>
 #include <string>
+#include <vector>
+
+#include <nanobind/eval.h>
+#include <nanobind/nanobind.h>
+#include <nanobind/stl/string.h>
 
 #include "Exception.hpp"
 
@@ -46,28 +49,34 @@ except Exception as e:
 [[gnu::visibility("default")]] void counts(const char *_circuit, const char *_device, size_t shots,
                                            size_t num_qubits, const char *_kwargs, void *_vector)
 {
-    namespace py = pybind11;
-    using namespace py::literals;
+    namespace nb = nanobind;
+    using namespace nb::literals;
 
-    py::gil_scoped_acquire lock;
+    nb::gil_scoped_acquire lock;
 
-    auto locals = py::dict("circuit"_a = _circuit, "device"_a = _device, "kwargs"_a = _kwargs,
-                           "shots"_a = shots, "msg"_a = "");
+    nb::dict locals;
+    locals["circuit"] = _circuit;
+    locals["device"] = _device;
+    locals["kwargs"] = _kwargs;
+    locals["shots"] = shots;
+    locals["msg"] = "";
 
-    py::exec(program, py::globals(), locals);
+    // Evaluate in scope of main module
+    nb::object scope = nb::module_::import_("__main__").attr("__dict__");
+    nb::exec(nb::str(program.c_str()), scope, locals);
 
-    auto &&msg = locals["msg"].cast<std::string>();
+    auto msg = nb::cast<std::string>(locals["msg"]);
     RT_FAIL_IF(!msg.empty(), msg.c_str());
 
-    py::dict results = locals["counts"];
+    nb::dict results = locals["counts"];
 
     std::vector<size_t> *counts_value = reinterpret_cast<std::vector<size_t> *>(_vector);
     for (auto item : results) {
         auto key = item.first;
         auto value = item.second;
-        counts_value->push_back(value.cast<size_t>());
+        counts_value->push_back(nb::cast<size_t>(value));
     }
     return;
 }
 
-PYBIND11_MODULE(oqc_python_module, m) { m.doc() = "oqc"; }
+NB_MODULE(oqc_python_module, m) { m.doc() = "oqc"; }