Array#to_enum

Array_to_enum.rb

class Array
  def to_enum
    Array.new(self.size, &lambda { |n| self[n].is_a?(Hash) ?  self[n] : {:"#{self[n]}" => n}} ).inject({}) {|m, w| m.merge!(w) }
  end
end

FRUIT = [:apple, :orange, :strawberry].to_enum

puts FRUIT[:apple]
>> 0
puts FRUIT[:orange]
>> 1
puts FRUIT[:strawberry]
>> 2


COLORS = [{:red => 6}, :green, :blue].to_enum

puts COLORS[:red]
>> 6
puts COLORS[:green]
>> 1
puts COLORS[:blue]
>> 2