foo = {a={},b={},c={"bar"},d={e={},f={"moo"}},1,2,3,4,5}
bar = {"alpha", "beta", "theta", omega = {}}

Example code:

local mytraverser = traverse()
mytraverser:enqueue("bar")
mytraverser:enqueue("foo")
for p,t,k,v in mytraverser() do
--for p,t,k,v in traverse('foo') do                                                                
    print(string.format("%s[%s] = %s",tostring(p),tostring(k),tostring(v)))                        
end

Outputs:

bar[1] = alpha
bar[2] = beta
bar[3] = theta
bar[omega] = table: 0x50ec10
foo[1] = 1
foo[2] = 2
foo[3] = 3
foo[4] = 4
foo[5] = 5
foo[a] = table: 0x50c270
foo[c] = table: 0x50cc00
foo[b] = table: 0x50c4d0
foo[d] = table: 0x50d1d0
foo.c[1] = bar
foo.d[e] = table: 0x50c3a0
foo.d[f] = table: 0x50cf60
foo.d.f[1] = moo