arrayfields allow keyword access to array instances.
arrayfields works by adding only a few methods to arrays,
namely #fields= and fields, but the #fields= method is
hooked to extend an array on a per object basis.In
otherwords __only__ those arrays whose fields are set
will have auto-magical keyword access bestowed on
them - all other arrays remain unaffected.arrays with
keyword access require much less memory when compared
to hashes/objects and yet still provide fast lookup and
preserve data order.

WWW: https://github.com/ahoward/arrayfields/tree/master