On Oct 21, 9:04 pm, "Meikel Brandmeyer (kotarak)" <m...@kotka.de> wrote: > Hi, > > may I question the transitivity of state information? > > Maybe the world's state is that player "Trantor" is at position [15 34]. Now > Trantor eats an appel. The appel is removed from his inventory and his > health is raised by 5 hit points. Did the state of the world change? No. > Trantor is still at position [15 34]. Does the world have to know about the > apple in Trantors inventory and the sad state of his hit points? > > Disclaimer: I have no clue about game programming, about what information is > needed where and how this is implemented insanely fast. Just a naive > question from the distance.
I think it generally makes sense to consider the entire world including Trantor and his tasty apple as part of the world state. This seems logically consistent - they are part of the world and it would seem odd if some actions like dropping an apple on the ground at [15 34] altered the world state but eating an apple didn't. It also has nice properties..... you can then treat the world state as a single value that you can pass to functions etc. e.g. you could create a higher order functions to update the world with something like: ((command "Trantor" :eat "apple") world-state) The problem with identities of actors comes in when you consider code like the following: (def trantor (get-actor "Trantor" world-state)) (:hit-points trantor) => 10 (def new-world-state ((command "Trantor" :eat "apple") world-state)) (:hit-points trantor) => 10 (still!! because we took a snapshot of trantor......) (def new-trantor (get-actor "Trantor" new-world-state)) (:hit-points new-trantor) => 15 Maybe this is all fine and I'm sure it is possible to successfully write a game this way. However it does feel a little strange when you are coming from OOP languages where you are used to simulating everything with mutable state.... -- 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 Note that posts from new members are moderated - please be patient with your first post. 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
