如何从表成员中引用lua表成员？

local table_name = {
    key1 = "value1",
    key2 = "value2"
}

local value1 = table_name.key1

local table_name = {
    key1 = "value1",
    key2 = "value2"
}

local value1 = table_name["key1"]

local table_name = {
    nested_table = {
        key1 = "value1",
        key2 = "value2"
    }
}

local value1 = table_name.nested_table.key1
local value2 = table_name["nested_table"].key2

local table_name = {
    key1 = "value1",
    key2 = "value2"
}

local key_name = "key1"
local value1 = table_name[key_name]

local table_name = {
    key1 = "value1",
    key2 = "value2"
}

local value1 = rawget(table_name, "key1")

local table_name = {
    key1 = "value1",
    key2 = "value2"
}

for key, value in pairs(table_name) do
    print(key .. ": " .. value)
end