Rough sketch of the internal organisation for game app. Is this kind of thing safe with respect to potentially overlapping calls of the various methods on rooms that might iterate over it while other methods add/delete from it?

gistfile1.rb

class Webapp
  include Reel::App

  get '/' do
    rooms = Actor[:rooms].list_rooms
    # serialize and stuff here
  end

  post '/:room' do
    # do some stuff
    Actor[:rooms].add(room)
  end

  post '/:room/:dice' do
     Actor[:rooms].roll_dice(room, dice)
  end
end

# Maybe other ways of interacting with Rooms here, e.g. a TCP server too.



# Talking with @benlangfeld, I'd be safe, so long as there were no methods
# on actors called by any of the methods on Rooms, which could then interrupt
# the otherwise serial nature of the calls.
# He therefore suggested using an immutable structure, such as those provided
# by Hamster.
class Rooms
  include Celluloid::Actor
  
  def initialize
    @rooms = Hamster.hash
  end

  # Add room to app
  def add(room)
    # make a new room.  Probably a PORO, maybe another actor.
  end

  # list rooms iterates over rooms
  def list_rooms
    @rooms.map { |id, room| [id, room.title] } 
  end

  # this might delete rooms from the hash
  every(60) { check_for_empty_rooms }
end