Temporary workaround for pybind11 bug

src/Python/pytnl/tnl/Array.h

@@ -8,6 +8,21 @@ namespace py = pybind11;
 
 #include <TNL/Containers/Array.h>
 
+
+// pybind11 should actually take care of this inside py::format_descriptor, but apparently it does not work...
+// see https://github.com/pybind/pybind11/issues/2135
+template< typename T, typename = void >
+struct underlying_type
+{
+   using type = T;
+};
+template< typename T >
+struct underlying_type< T, std::enable_if_t< std::is_enum< T >::value > >
+{
+   using type = std::underlying_type_t< T >;
+};
+
+
 template< typename ArrayType >
 void export_Array(py::module & m, const char* name)
 {
@@ -49,7 +64,9 @@ void export_Array(py::module & m, const char* name)
                 // Size of one scalar
                 sizeof( typename ArrayType::ValueType ),
                 // Python struct-style format descriptor
-                py::format_descriptor< typename ArrayType::ValueType >::format(),
+                py::format_descriptor<
+                     typename underlying_type< typename ArrayType::ValueType >::type
+                >::format(),
                 // Number of dimensions
                 1,
                 // Buffer dimensions