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>

README.md

@@ -66,18 +66,18 @@ Since `matchbot` uses Clojure's [tools.deps library](https://clojure.org/guides/
 You can create, start and stop an instance of the chatbot process with the functions in the `system` namespace:
 
 ``` clojure
-;; creating a new instance
-(def my-instance (atom (system/system)))
+;; creating a new instance - an empty Var
+(def my-instance nil)
 
 ;; starting the instance
-(swap! my-instance system/start)
+(alter-var-root #'my-instance system/start)
 
 ;; restarting the instance
-(system/restart my-instance)
+(system/restart #'my-instance)
 
 ;; stopping and resetting the instance
-(swap! my-instance stop)
-(reset! my-instance (system/system))
+(alter-var-root #'my-instance system/stop)
+(alter-var-root #'my-instance (constantly nil))
 ```
 
 Once you are familiar with nREPL, you can additionally use [tools.namespace.repl](https://github.com/clojure/tools.namespace) to make reevaluating (reloading) your changes easier:

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
@@ -34,12 +34,7 @@
       (yaml/parse-stream datafile))
     (catch Exception e nil)))
 
-(defn system []
-  {:config nil
-   :state nil
-   :irc nil})
-
-(defn start [system]
+(defn start [_]
   (let [config (load-config "config.yaml")
         state (atom (load-state (:data-file config)))
         irc (irc/new-irc-connection state config)]
@@ -55,14 +50,12 @@
      (deref (:state system)))
     (irclj.core/quit (system :irc))))
 
-(defn restart [system-atom]
+(defn restart [system-var]
   (do
-    (swap! system-atom stop)
-    (reset! system-atom (system))
-    (swap! system-atom start)))
+    (stop (deref system-var))
+    (alter-var-root system-var start)))
 
 (defn -main [& args]
-  (let [main-system (atom (system/system))]
-    (swap! main-system system/start)
+  (let [main-system (system/start nil)]
     (.addShutdownHook (Runtime/getRuntime)
-                      (Thread. (partial swap! main-system stop)))))
+                      (Thread. #(stop main-system)))))