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: http://codeforpeople.com/lib/ruby/arrayfields/