Add void as a possible type for functions return type

src/language/BuiltinFunctionEmbedder.hpp

@@ -17,6 +17,8 @@
 template <typename T>
 inline ASTNodeDataType ast_node_data_type_from = ASTNodeDataType::undefined_t;
 
+template <>
+inline ASTNodeDataType ast_node_data_type_from<void> = ASTNodeDataType::void_t;
 template <>
 inline ASTNodeDataType ast_node_data_type_from<bool> = ASTNodeDataType::bool_t;
 template <>

src/language/MeshModule.cpp

@@ -29,10 +29,10 @@ MeshModule::MeshModule()
                                           ));
 
   this->_addBuiltinFunction("writeVTK",
-                            std::make_shared<BuiltinFunctionEmbedder<double, std::shared_ptr<IMesh>, std::string>>(
-                              std::function<double(std::shared_ptr<IMesh>, std::string)>{
+                            std::make_shared<BuiltinFunctionEmbedder<void, std::shared_ptr<IMesh>, std::string>>(
+                              std::function<void(std::shared_ptr<IMesh>, std::string)>{
 
-                                [](std::shared_ptr<IMesh> p_mesh, std::string filename) -> double {
+                                [](std::shared_ptr<IMesh> p_mesh, std::string filename) -> void {
                                   VTKWriter writer(filename, 0);
 
                                   switch (p_mesh->dimension()) {
@@ -58,8 +58,6 @@ MeshModule::MeshModule()
                                     break;
                                   }
                                   }
-
-                                  return 0;
                                 }
 
                               }));