require 'active_support/all'

@store = ActiveSupport::HashWithIndifferentAccess.new

def my_hash
  @store[:foo] ||= {bar: 'BAR'}
end

my_hash[:waldo] = 'WALDO'
my_hash[:baz] = 'BAZ'
my_hash[:qux] = 'QUX'

puts my_hash