no. in fact, having the array part is quite handy to store a desired
order on a hashtable (which is intrinsically unsorted). see how
luaExpat reports XML argument lists
As long as a hash table value can be a vector (and vice versa) it is easy to have both hash and vector parts of your data structure.
The issue (as I see it) with Lua is that it forces you to have both all the time (and suffer the consequences on things like #t)
