Compile error on .addConstructor(LUA_ARGS(_opt<std::string>))

[rvt]

Hey,

I am getting the below compile error.
What could be the cause of it?
I did add the lib as headers only, but also tried compiling as cpp.

Ries

In file included from ./lua-intf/LuaIntf.h:27:
In file included from ./lua-intf/LuaIntf/LuaIntf.h:32:
In file included from ./lua-intf/LuaIntf/LuaContext.h:32:
./lua-intf/LuaIntf/LuaRef.h:1098:36: warning: unused parameter 'L' [-Wunused-parameter]
    static void pushArg(lua_State* L)
                                   ^
In file included from cad/lualibrecadbridge.cpp:6:
In file included from ./lua-intf/LuaIntf.h:27:
In file included from ./lua-intf/LuaIntf/LuaIntf.h:40:

..
..
./lua-intf/LuaIntf/impl/CppInvoke.h:236:32: warning: unused parameter 'L' [-Wunused-parameter]
    static int push(lua_State* L, T* t, const FN& func, std::tuple& args)
                               ^
cad/lualibrecadbridge.cpp:26:25: error: type name requires a specifier or qualifier
        .addConstructor(LUA_ARGS(_opt))
                        ^
./lua-intf/LuaIntf/impl/CppArg.h:49:35: note: expanded from macro 'LUA_ARGS'
#define LUA_ARGS(...) static_cast(nullptr)
                                  ^
./lua-intf/LuaIntf/impl/CppArg.h:48:28: note: expanded from macro 'LUA_ARGS_TYPE'
#define LUA_ARGS_TYPE(...) _arg(*)(__VA_ARGS__)
                           ^
cad/lualibrecadbridge.cpp:26:25: error: expected '>'
./lua-intf/LuaIntf/impl/CppArg.h:49:35: note: expanded from macro 'LUA_ARGS'
#define LUA_ARGS(...) static_cast(nullptr)
                                  ^
./lua-intf/LuaIntf/impl/CppArg.h:48:28: note: expanded from macro 'LUA_ARGS_TYPE'
#define LUA_ARGS_TYPE(...) _arg(*)(__VA_ARGS__)
                           ^
cad/lualibrecadbridge.cpp:26:25: note: to match this '<'
./lua-intf/LuaIntf/impl/CppArg.h:49:34: note: expanded from macro 'LUA_ARGS'
#define LUA_ARGS(...) static_cast(nullptr)
                                 ^
7 warnings and 2 errors generated.
make: *** [generated/obj/lualibrecadbridge.o] Error 1

[SteveKChiu]

VA_ARGS does not expand correctly. Can you post the compile command line? It is more like you forget to enable some flags.

[rvt]

Hey Steve,

I figured out what the reason was, I had to use using namespace LuaIntf; in my code rather then using LuaIntf::LuaBinding(L), so now it's all working fine.

I do have a other question if you don't mind:

I am using boost I'm my application and noticed that the function LuaCppObjectFactory uses static cast, however I believe with boost you need to use static_pointer_cast. so I hacked it and changed it to : return boost::static_pointer_cast<CppObjectSharedPtr<SP, T>>(obj)->sharedPtr();

That seem to work fine, any suggestions for a proper fix? I was thinking to do something like
LUA_USING_STATIC_CAST_TYPE(boost::static_pointer_cast) but I am not sure if that's truly the right solution as my daily work isn't c++ but java.

[SteveKChiu]

No, it is not necessary, the original code works fine. boost::static_pointer_cast (and std::static_pointer_cast) is to cast shared_ptr<T> to shared_ptr<U>, and LuaIntf don't do that kind of casting.

However, I do find a bug in the static_cast of the following line:

        return static_cast<CppObjectSharedPtr<SP, T>>(obj)->sharedPtr();

should be:

        return static_cast<CppObjectSharedPtr<SP, T>*>(obj)->sharedPtr();

ah, miss a '*'. I really need to add more testing, I will add them later.

[rvt]

Hello Steve,

thanks for taking a look at this and tomorrow morning I am going to take a second look at the change I made and see if I can go without the change I made.

Currently I have everything working with your library, and the use of shared pointer's , this is the code I am currently working on : https://github.com/rvt/kerneldev/blob/master/lcadluascript/cad/lualibrecadbridge.cpp

Background, I am working on a new version of LibreCAD and with lua scripting we can start testing functionality without adding UI functionality by simply scripting it.