convert hash to object with OpenStruct

require 'ostruct'
class Object
  def hash_to_ostruct(visited = [])
    self
  end
end

class Array
  def hash_to_ostruct(visited = [])
    map { |x| x.hash_to_ostruct(visited) }
  end
end

class Hash
   def hash_to_ostruct(visited = [])
     os = OpenStruct.new
     each do |k, v|
       item = visited.find { |x| x.first.object_id == v.object_id }
       if item
        os.send("#{k}=", item.last)
       else
        os.send("#{k}=", v.hash_to_ostruct(visited + [ [self, os] ]))
       end
     end
     os
   end
end 

hash = { "country" => {:a => "a"}, :population => 20_000_000 }
p hash.hash_to_ostruct