One way to approach this without mutation is as follows: Decide on a data representation that represents the entire state of the game world at a given instant.
Write a function which can draw this state. Write a function which takes the state and player keypresses as input, and returns a new updated state. Write a function which takes the state and returns the new state just from time elapsing. Note that none of the above functions mutate anything. It's all about returning fresh states, which fits well with Clojure's standard handling of data structures. Then write a loop that consumes an initial state, and creates a game experience by repeatedly applying the above functions. No globals or refs are required, just keep passing the new states back into the loop for further processing. This is an outline of the strategy employed by the "world" teachpack that accompanies the "How to Design Programs" curriculum that uses PLT Scheme. Students routinely develop the snake program as a homework assignment, using this approach. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
