# File lib/rdoc/ri/driver.rb, line 905
  def list_known_classes names = []
    classes = []

    stores.each do |store|
      classes << store.modules
    end

    classes = classes.flatten.uniq.sort

    unless names.empty? then
      filter = Regexp.union names.map { |name| /^#{name}/ }

      classes = classes.grep filter
    end

    page do |io|
      if paging? or io.tty? then
        if names.empty? then
          io.puts "Classes and Modules known to ri:"
        else
          io.puts "Classes and Modules starting with #{names.join ', '}:"
        end
        io.puts
      end

      io.puts classes.join("\n")
    end
  end