refactor clear-and-get-evalqueue into the reusable reset-returning-old!

src/hottub/repl.clj

@@ -1,4 +1,5 @@
 (ns hottub.repl
+  (:use hottub.util)
   (:require (clojure.tools.nrepl [server :as server]
                                  [middleware :as middleware])
             (clojure.tools.nrepl.middleware pr-values
@@ -34,15 +35,8 @@
   (server/stop-server @(:server repl))
   (reset! (:server repl) nil))
 
-(defn clear-and-get-evalqueue [repl]
-  (let [evalqueueatom (:evalqueue repl)]
-    (loop [evalqueue @evalqueueatom]
-      (if (compare-and-set! evalqueueatom evalqueue [])
-        evalqueue
-        (recur @evalqueueatom)))))
-
 (defn repl-update [repl]
-  (doseq [f (clear-and-get-evalqueue repl)] 
+  (doseq [f (reset-returning-old! (:evalqueue repl) [])] 
     (try
       (f)
       (catch Exception e (println "couldn't eval:" (.getMessage e))))))

src/hottub/util.clj

@@ -0,0 +1,7 @@
+(ns hottub.util)
+
+(defn reset-returning-old! [a newval]
+  (loop [oldval @a]
+    (if (compare-and-set! a oldval newval)
+        oldval
+        (recur @a))))