mytable = {
   indexname = value,
   ...
   pos = {0.0,0.0},
   ...
}

function foo()
   mytable.pos = GetPosition()
   ...
   mytable.pos[1] = mytable.pos[1] + somevalue
   mytable.pos[2] = mytable.pos[2] + anothervalue
   SetPosition(mytable.pos[1],mytable.pos[2])
end

int CSpriteBehaviorScript::GetPosition(lua_State* L)
{
	CRect<int> rect = mSprite->GetRect(); // get the position

	lua_newtable(L); // create the return value table and put it on a stack

	// push index[1] to the table
	lua_pushnumber(L, 1);
	lua_pushnumber(L, rect.x);
	lua_settable(L, -3);

	// push index[2] to the table
	lua_pushnumber(L, 2);
	lua_pushnumber(L, rect.y);
	lua_settable(L, -3);

	return 1; // pass one return value to lua
}

-- Craft sizeSize = SYM_VECTOR3(20, 10, 40)-- Thruster placementThrusters = { 	SYM_VECTOR3( Size.x * 0.6, Size.y * 0.1,  Size.z * 0.6),				SYM_VECTOR3(-Size.x * 0.6, Size.y * 0.1,  Size.z * 0.6),				SYM_VECTOR3( Size.x * 0.6, Size.y * 0.1,  0.0),				SYM_VECTOR3(-Size.x * 0.6, Size.y * 0.1,  0.0),				SYM_VECTOR3( Size.x * 0.6, Size.y * 0.1, -Size.z * 0.6),				SYM_VECTOR3(-Size.x * 0.6, Size.y * 0.1, -Size.z * 0.6)}...function oOnApplyForceAndTorque(GeomName)	if GeomName == "HCraft"	then						-- Get matrix		Matrix = getmatrix("HCraft")			-- Get hovercraft omega		Omega = getomega("HCraft")		-- Get force direction in global space		ThrusterDir = Matrix:UnrotateVector(SYM_VECTOR3(0, 1, 0))		TotalForce = GravityForce		TotalTorque = SYM_VECTOR3(0, 0, 0)			-- Loop through thrusters		for i = 1,6		do			-- **ERROR OCCURS HERE**			io.write(Thrusters.x.."  "..Thrusters.y.."  "..Thrusters.z.."\n")			-- Get thruster position in global space			ThrusterPos = Matrix:TransformVector(Thrusters)...