Add utility package with register_map for std::map.

src/runner/pythonutils.h

@@ -0,0 +1,58 @@
+#ifndef PYTHONRUNNER_UTILS_H
+#define PYTHONRUNNER_UTILS_H
+
+#include <boost/python.hpp>
+
+namespace utils {
+
+  template <class Map>
+  struct map_to_python {
+    static PyObject* convert(const Map& map) {
+      boost::python::dict result;
+      for (auto& entry : map) {
+        result[boost::python::object{ entry.first }] = boost::python::object{ entry.second };
+      }
+      return boost::python::incref(result.ptr());
+    }
+  };
+
+  template <class Map>
+  struct map_from_python {
+
+    using key_type = typename Map::key_type;
+    using value_type = typename Map::mapped_type;
+
+    static void* convertible(PyObject* objPtr) {
+      return PyDict_Check(objPtr) ? objPtr : nullptr;
+    }
+
+    static void construct(PyObject* objPtr, boost::python::converter::rvalue_from_python_stage1_data* data) {
+      void* storage = ((boost::python::converter::rvalue_from_python_storage<Map>*)data)->storage.bytes;
+      Map* result = new (storage) Map();
+      boost::python::dict source(boost::python::handle<>(boost::python::borrowed(objPtr)));
+      boost::python::list keys = source.keys();
+      int len = boost::python::len(keys);
+      for (int i = 0; i < len; ++i) {
+        boost::python::object pyKey = keys[i];
+        (*result)[boost::python::extract<key_type>(pyKey)] = boost::python::extract<value_type>(source[pyKey]);
+      }
+
+      data->convertible = storage;
+    }
+  };
+
+  template <class Map>
+  void register_map() {
+
+    boost::python::to_python_converter<Map, map_to_python<Map>>();
+
+    boost::python::converter::registry::push_back(
+      &map_from_python<Map>::convertible
+      , &map_from_python<Map>::construct
+      , boost::python::type_id<Map>());
+  };
+
+
+}
+
+#endif