rails--rails/activesupport/lib/active_support/ordered_options.rb

require 'active_support/ordered_hash'

module ActiveSupport #:nodoc:
  class OrderedOptions < OrderedHash
    def []=(key, value)
      super(key.to_sym, value)
    end

    def [](key)
      super(key.to_sym)
    end

    def method_missing(name, *args)
      if name.to_s =~ /(.*)=$/
        self[$1.to_sym] = args.first
      else
        self[name]
      end
    end
  end
end