deep_fetch.rb

# utility for performing multiple fetches on hashes
# ex:
# h = {:foo => {:bar => :baz}}
# h.deep_fetch :foo, :bar
class Hash
  def deep_fetch(*keys, last_key)
    scope = self
    keys.each do |key|
      scope = scope.fetch key, {}
    end
    scope[last_key]
  end
end

Yep