Adding Python to/from string wrappers for internal IDs

common/pybindings.h

@@ -76,6 +76,54 @@ struct range_wrapper {
     }
 };
 
+/*
+A wrapper to enable custom type/ID to/from string conversions
+ */
+template <typename T> struct string_wrapper {
+	template<typename F>
+	struct from_pystring_converter {
+		from_pystring_converter() {
+			converter::registry::push_back(
+					&convertible,
+					&construct,
+					boost::python::type_id<T>());
+		};
+
+		static void* convertible(PyObject* object) {
+			return PyUnicode_Check(object) ? object : 0;
+		}
+
+		static void construct(
+				PyObject* object,
+				converter::rvalue_from_python_stage1_data* data) {
+			const wchar_t* value = PyUnicode_AsUnicode(object);
+			const std::wstring value_ws(value);
+			if (value == 0) throw_error_already_set();
+			void* storage = (
+					(boost::python::converter::rvalue_from_python_storage<T>*)
+							data)->storage.bytes;
+			new (storage) T(fn(std::string(value_ws.begin(), value_ws.end())));
+			data->convertible = storage;
+		}
+
+		static  F fn;
+	};
+
+	template<typename F> struct to_str_wrapper {
+		static F fn;
+		std::string str(T& x) {
+			return fn(x);
+		}
+	};
+
+	template<typename F1, typename F2> static void wrap(const char *type_name, F1 to_str_fn, F2 from_str_fn) {
+		from_pystring_converter<F2>::fn = from_str_fn;
+		from_pystring_converter<F2>();
+		to_str_wrapper<F1>::fn = to_str_fn;
+		class_<T>(type_name, no_init).def("__str__", to_str_wrapper<F1>::str);
+	};
+};
+
 #define WRAP_RANGE(t) range_wrapper<t##Range>().wrap(#t "Range", #t "Iterator")
 
 void init_python(const char *executable);