Lua实现__add方法重载示例

实现加法(__add)重载代码示例：

do
 local infor_class = {};

 function infor_class.create(_t)
  local newtable = {};
  setmetatable(newtable, infor_class); --set the metatable
  for i, v in pairs(_t) do
   newtable[i] = v;
  end
  return newtable;
 end

 function infor_class.sum(c1, c2)
  if(#c1 ~= #c2) then
   return nil;
  else
   local result = {};
   local len = #c1;
   for i = 1, len do
    result[i] = c1[i] + c2[i];
   end
   print("result");
   return result;
  end
  print("nil");
  return nil;
 end

 infor_class.__add = infor_class.sum --override the _add

 r1 = infor_class.create{3, 4}
 r2 = infor_class.create{5, 6};

 result = r1 + r2;
 print(unpack(result));
end