recursive output all the table content

function print_tbl(v_s) 
  if type(v_s) == "table" then
    print(v_s, "contents:-----------------------------------------------")
    for k,v in pairs(v_s) do 
      if type(v_s[k]) == "table" 
      then 
        print(v_s,k,v)
        print_tbl(v_s[k]) 
      else 
        print(v_s,k,v) 
      end 
    end
  else
    error("please enter a table variable.")
  end
end

> s = require("socket")

> print_tbl(s)
table: 0x15b9410        contents:-----------------------------------------------
table: 0x15b9410        dns     table: 0x15b95c0
table: 0x15b95c0        contents:-----------------------------------------------
table: 0x15b95c0        getaddrinfo     function: 0x7f5d2c2ded80
table: 0x15b95c0        gethostname     function: 0x7f5d2c2deb20
table: 0x15b95c0        toip    function: 0x7f5d2c2df1d0
table: 0x15b95c0        getnameinfo     function: 0x7f5d2c2deba0
table: 0x15b95c0        tohostname      function: 0x7f5d2c2df140
table: 0x15b9410        __unload        function: 0x7f5d2c2dc510
table: 0x15b9410        choose  function: 0x15bb6b0
table: 0x15b9410        sink    function: 0x15badc0
table: 0x15b9410        sourcet table: 0x15bb6e0
table: 0x15bb6e0        contents:-----------------------------------------------
table: 0x15bb6e0        default function: 0x15baee0
table: 0x15bb6e0        by-length       function: 0x15bae00
table: 0x15bb6e0        until-closed    function: 0x15baee0
table: 0x15b9410        skip    function: 0x7f5d2c2dc520
table: 0x15b9410        _VERSION        LuaSocket 3.0-rc1
table: 0x15b9410        source  function: 0x15bafd0
table: 0x15b9410        sleep   function: 0x7f5d2c2dc6b0
table: 0x15b9410        udp     function: 0x7f5d2c2e1450
table: 0x15b9410        BLOCKSIZE       2048
table: 0x15b9410        tcp     function: 0x7f5d2c2e0b30
table: 0x15b9410        _SETSIZE        1024
table: 0x15b9410        sinkt   table: 0x15bb730
table: 0x15bb730        contents:-----------------------------------------------
table: 0x15bb730        default function: 0x15bb7e0
table: 0x15bb730        close-when-done function: 0x15bb780
table: 0x15bb730        keep-open       function: 0x15bb7e0
table: 0x15b9410        newtry  function: 0x7f5d2c2dfe70
table: 0x15b9410        select  function: 0x7f5d2c2e0360
table: 0x15b9410        try     function: 0x15bbeb0
table: 0x15b9410        bind    function: 0x15b94c0
table: 0x15b9410        connect6        function: 0x15bbe50
table: 0x15b9410        protect function: 0x7f5d2c2dfda0
table: 0x15b9410        gettime function: 0x7f5d2c2dc7b0
table: 0x15b9410        connect4        function: 0x15b9640
table: 0x15b9410        connect function: 0x7f5d2c2e0780
table: 0x15b9410        udp6    function: 0x7f5d2c2e1440
table: 0x15b9410        tcp6    function: 0x7f5d2c2e0b20