Initial commit with working gamestate + indexing.

.gitignore

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+/pom.xml
+*jar
+/lib
+/classes
+/native
+/.lein-failures
+/checkouts
+/.lein-deps-sum

README

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+# hottub
+
+FIXME: write description
+
+## Usage
+
+FIXME: write
+
+## License
+
+Copyright (C) 2013 FIXME
+
+Distributed under the Eclipse Public License, the same as Clojure.

project.clj

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+(defproject hottub "1.0.0-SNAPSHOT"
+  :description "Hot Tub Time Machine Game Engine"
+  :dependencies [[org.clojure/clojure "1.5.0"]])

src/hottub/gs.clj

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+(ns hottub.gs)
+
+(defmulti update-index (fn [indextype indexold id entityold entitynew] indextype))
+(defmulti query-index (fn [indextype index query] indextype))
+
+
+(def gs-empty {:entities {} :indices {} :id-lim 0})
+
+(def ^:dynamic *gamestate* (ref gs-empty))
+(defn gen-id []
+  (let [id (:id-lim @*gamestate*)]
+    (ref-set *gamestate* (assoc @*gamestate* :id-lim (+ id 1)))
+    id))
+
+(defmacro with-gs [gs & body]
+  `(binding [*gamestate* (ref ~gs)] (dosync ~@body)))
+
+(defn get-gs [] @*gamestate*)
+
+(defn entity [id] (get-in @*gamestate* [:entities id]))
+
+(defn- update-indices [id entityold entitynew]
+  (ref-set *gamestate*
+    (loop [gs @*gamestate* indextypes (keys (:indices gs))]
+      (if (seq indextypes)
+        (let [indextype (first indextypes)
+              indexold (get-in gs [:indices indextype])
+              indexnew (update-index indextype indexold id entityold entitynew)
+              gsnew (assoc-in gs [:indices indextype] indexnew)]
+          (recur gsnew (next indextypes)))
+        gs))))
+
+(defn add-index [indextype]
+  (ref-set *gamestate*
+  	(loop [index {} ids (keys (:entities @*gamestate*))]
+      (if (seq ids)
+        (let [id (first ids)
+              indexnew (update-index indextype index id nil (entity id))]
+          (recur indexnew (next ids)))
+        (assoc-in @*gamestate* [:indices indextype] index)))))
+
+(defn remove-id-from-index [index id key]
+  (if-let [idsbefore (get index key)] 
+    (let [idsafter (disj idsbefore id)]
+      (if (empty? idsafter)
+        (dissoc index key)
+        (assoc index key idsafter)))
+    index))
+
+(defn add-id-to-index [index id key]
+  (if-let [idsbefore (get index key)]
+    (assoc index key (conj idsbefore id))
+    (if key
+      (assoc index key #{id}) 
+      index)))
+
+(defn set-entity [id value] 
+  (update-indices id (entity id) value)
+  (let [gsnew 
+  	(if (= value nil)
+      (assoc @*gamestate* :entities (dissoc (get @*gamestate* :entities) id))
+      (assoc-in @*gamestate* [:entities id] value))]
+    (ref-set *gamestate* gsnew)))
+
+(defn q [indextype query]
+  (query-index indextype (get-in @*gamestate* [:indices indextype]) query))
+
+(defmethod update-index :name [indextype indexold id entityold entitynew] 
+  (-> indexold
+      (remove-id-from-index id (get entityold :name))
+      (add-id-to-index id (get entitynew :name))))
+
+(defmethod query-index :name [indextype index query] (or (get index query) #{}))
+