From 9bb4f0a1e46e68b5996887c7573413464f460685 Mon Sep 17 00:00:00 2001
From: oakes <zsoakes@gmail.com>
Date: Thu, 9 Jan 2014 17:06:56 -0500
Subject: [PATCH] Improve ability to modify entities via the REPL

---
 src/play_clj/core.clj | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/play_clj/core.clj b/src/play_clj/core.clj
index a2b84dc..f17588f 100644
--- a/src/play_clj/core.clj
+++ b/src/play_clj/core.clj
@@ -44,11 +44,12 @@
   (let [screen (atom {})
         entities (atom '())
         execute-fn! (fn [func screen-map]
-                      (some->> (func screen-map @entities)
-                               list
-                               flatten
-                               (remove nil?)
-                               (reset! entities)))
+                      (let [entities-list @entities]
+                        (some->> (func screen-map entities-list)
+                                 list
+                                 flatten
+                                 (remove nil?)
+                                 (compare-and-set! entities entities-list))))
         create-renderer-fn! #(swap! screen assoc :renderer (renderer %))
         update-fn! #(swap! screen merge %)]
     {:screen screen