How to use .addFunction for class methods which returns std:vectors using Luabridge

Question

I have a class like this in Visual Studio C++ 2012 (with C++ v.11):

#pragma once
#include <vector>
struct Object
{
public:
    std::string _name;
    double _number;
    std::vector<double> _list;
public:
    Object();
    Object(std::string, double);
    ~Object(void);
    std::string getname();
    double getnumber();
    void setname(std::string name);
    void setnumber(double number);
    std::vector<double>& getlist();
};

double Object::getnumber()
{
    return _number;
}

std::vector<double>& Object::getlist()
{
    return _list;
}

And a main which contains something like this:

lua_State* L = luaL_newstate();
luaL_openlibs(L);

luabridge::getGlobalNamespace (L)
    .beginClass<std::vector<double>> ("DoubleVector")
        .addFunction("size1", &std::vector<double>::size) 
        .addFunction<std::vector<double>::reference (std::vector<double>::*)(std::vector<double>::size_type)>("at1", &std::vector<double>::at)
    .endClass()

    .beginClass <Object> ("Object") 
        .addConstructor<void(*) (void)>()
        .addConstructor<void(*) (std::string, double)>()
        .addFunction("getname",&Object::getname)
        .addFunction("getnumber",&Object::getnumber)
        .addFunction("setname",&Object::setname)    
        .addFunction("setnumber",&Object::setnumber)
        .addFunction("getlist",&Object::getlist)
    .endClass()

    .beginClass<std::vector<Object>> ("ObjectVector")
        .addFunction("size", &std::vector<Object>::size) 
        .addFunction<std::vector<Object>::reference (std::vector<Object>::*)(std::vector<Object>::size_type)>("at", &std::vector<Object>::at)
    .endClass()
    ;


Object obj1("Primer objeto", 1), obj2("Segundo objeto", 2);
obj1.getlist().push_back(11);
obj1.getlist().push_back(22);

obj2.getlist().push_back(111);
obj2.getlist().push_back(222);
obj2.getlist().push_back(333);

std::vector<Object> v;
v.push_back(obj1);
v.push_back(obj2);

luabridge::push(L, &v);
lua_setglobal(L, "v");

std::string path = "C:\\file.lua";
luaL_dofile(L, path.c_str());

luabridge::LuaRef number = luabridge::getGlobal(L, "number");
double luaNumber = number.cast<double>();
std::cout << "value:" << luaNumber << std::endl << std::endl;

I have no problems with any method except getlist(). Specifically I have problems doing from Lua something like this with getlist():

number = v:at(1):getlist():at1(2);

Debugging with Visual Studio C++ 2012 I get the following message:

Assertion failed: lua_istable(L, -1), file c:\luabridge\detail\userdata.h, line 412. Error R6010 - abort() has been called

I think that the problem is that I am calling a method which returns a complex type (an object, specifically a std:vector), and not a simple type like the other methods, because in Lua, this fails:

number = v:at(1):getlist():at1(2);

And this works:

number = v:at(1):getnumber();

How can I fix this? (Remember that I can't change the Object class because it's a class that we use at work an it must be like this. I need a solution using luabridge).

Answer 1

The issue does not exist on LuaBridge 2.6. But the "at" function should be changed to

        .addFunction("at",
            std::function <double(std::vector<double>*, int)>(
                [](std::vector<double>* vec, int i) { return (*vec)[i - 1]; }))

And be sure do NOT have #include <LuaBridge/Vector.h>.