Move processing out of clojure.data.json/read call

This commit removes from the call to clojure.data.json/read the
conversion of the serialised list of players into a Clojure set, and
adds an independent function to do this task instead.

Since the structure of the serialised data is known in advance, the
recursive characteristics of clojure.data.json are not needed.

Resolves issue LibreGaming/matchbot#4

Signed-off-by: Sebastian Crane <seabass-labrax@gmx.com>

src/system.clj

@@ -6,21 +6,21 @@
             [clojure.data.json :as json]
             [clj-yaml.core :as yaml]))
 
-(defn json-data-reader [key value]
-  (if (= key :games)
-    (into (empty value)
-          (map #(hash-map (first %)
-                          (set (second %)))
-               value))
-    value))
+(defn setify-vals [x]
+  (reduce #(assoc %1
+                  (first %2)
+                  (set (second %2)))
+          {} x))
+
+(defn process-json [x]
+  (update x :games setify-vals))
 
 (defn load-state [f]
-  (try
-    (with-open [datafile (clojure.java.io/reader f)]
-      (json/read datafile
-                 :value-fn json-data-reader
-                 :key-fn keyword))
-    (catch Exception e nil)))
+  (process-json
+   (try
+     (with-open [datafile (clojure.java.io/reader f)]
+       (json/read datafile :key-fn keyword))
+     (catch Exception e nil))))
 
 (defn save-state [f data]
   (try