lua实现深度拷贝table表

deepcopy = function(object)
    local lookup_table = {}
    local function _copy(object)
        if type(object) ~= "table" then
            return object
        elseif lookup_table[object] then
            return lookup_table[object]
        end
        local new_table = {}
        lookup_table[object] = new_table
        for index, value in pairs(object) do
            new_table[_copy(index)] = _copy(value)
        end
        return setmetatable(new_table, getmetatable(object))
    end

    return _copy(object)
end

local testA =  {1,2,3,4,5}

local testB = testA
testB[2] = "我擦"

local testC = deepcopy(testA)
testC[2] = "我勒个去"

for k , v  in ipairs (testA) do
    print("testA",k, v )
end

print("============================")

for k , v  in ipairs (testC) do
    print("testC",k, v )
end