# File lib/arrayfields.rb, line 389
      def [](*pairs)
        pairs.flatten!
        raise ArgumentError, "argument must be key/val pairs" unless 
          (pairs.size % 2 == 0)
        fields, elements = [], []
        while((f = pairs.shift) and (e = pairs.shift)) 
          fields << f and elements << e
        end
        new fields, elements
      end