#define SOL_ALL_SAFETIES_ON 1 #include #include struct two_things { int a; bool b; }; template bool sol_lua_check(sol::types, lua_State* L, int index, Handler&& handler, sol::stack::record& tracking) { // indices can be negative to count backwards from the top // of the stack, rather than the bottom up to deal with // this, we adjust the index to its absolute position using // the lua_absindex function int absolute_index = lua_absindex(L, index); // Check first and second second index for being the proper // types bool success = sol::stack::check(L, absolute_index, handler) && sol::stack::check( L, absolute_index + 1, handler); tracking.use(2); return success; } two_things sol_lua_get(sol::types, lua_State* L, int index, sol::stack::record& tracking) { int absolute_index = lua_absindex(L, index); // Get the first element int a = sol::stack::get(L, absolute_index); // Get the second element, // in the +1 position from the first bool b = sol::stack::get(L, absolute_index + 1); // we use 2 slots, each of the previous takes 1 tracking.use(2); return two_things { a, b }; } int sol_lua_push(lua_State* L, const two_things& things) { int amount = sol::stack::push(L, things.a); // amount will be 1: int pushes 1 item amount += sol::stack::push(L, things.b); // amount 2 now, since bool pushes a single item // Return 2 things return amount; } int main() { std::cout << "=== customization ===" << std::endl; std::cout << std::boolalpha; sol::state lua; lua.open_libraries(sol::lib::base); // Create a pass-through style of function lua.script( "function f ( a, b ) print(a, b) return a, b end"); // get the function out of Lua sol::function f = lua["f"]; two_things things = f(two_things { 24, false }); SOL_ASSERT(things.a == 24); SOL_ASSERT(things.b == false); // things.a == 24 // things.b == true std::cout << "things.a: " << things.a << std::endl; std::cout << "things.b: " << things.b << std::endl; std::cout << std::endl; return 0; }