# File lib/rdoc/ri/driver.rb, line 584
  def classes
    return @classes if @classes

    @classes = {}

    @stores.each do |store|
      store.cache[:modules].each do |mod|
        # using default block causes searched-for modules to be added
        @classes[mod] ||= []
        @classes[mod] << store
      end
    end

    @classes
  end