Henning Thielemann wrote:
A dungeon game? :-)
Yes. :-) Thank you all for your answers! I especially like David's no-intermediate-structure solution because it allows for defining the area in terms of neighbours instead of needing an index on the rooms. Now that I have core functionality in my game I want to try and build some interesting areas, such as infinite ones: a infinite grid, or an N-dimensional Hilbert curve. Because rooms are mutable, I am building them inside a state monad and use ids: mkRoom :: M RoomId addExit :: RoomId -> Exit -> M () type Exit = (String, RoomId) I thought my original question would give me some ideas on how to construct infinite areas, but this monadic interface complicates things somewhat. If I create all rooms at once, runState never returns, so I will have to create them lazily, perhaps by changing: type Exit = M (String, RoomId) But I think in addition to that I will also needs refs, so that the monadic computation can check using a ref whether it's created its target room before. I will have to experiment and think on this some more. Martijn.