From f8506819af6f5101e23310ca7e9a3f3607ef269f Mon Sep 17 00:00:00 2001
From: Jeremy Dormitzer <jeremy.dormitzer@gmail.com>
Date: Thu, 9 Aug 2018 22:10:05 -0400
Subject: [PATCH] Implement := operator

---
 src/performance.clj | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/performance.clj b/src/performance.clj
index 39784cc..ecb0bb8 100644
--- a/src/performance.clj
+++ b/src/performance.clj
@@ -35,6 +35,19 @@
    :volume 50           ;; volume of performance
    :key [:C :major]})   ;; current key signature
 
+(defn merge-perfs
+  "Merges two performances"
+  [p1 p2]
+  (if (nil? (seq p1))
+    p2
+    (if (nil? (seq p2))
+      p1
+      (let [e1 (first p1)
+            e2 (first p2)]
+        (if (< (:duration e1) (:duration e2))
+          (into [e1] (merge-perfs (rest p1) p2))
+          (into [e2] (merge-perfs p1 (rest p2))))))))
+
 (defn perform
   "Convert a music value to a performance value"
   [player-map context music]
@@ -56,11 +69,18 @@
                               (let [[events dur] (perf player-map
                                                        context
                                                        m)]
-                                [(concat events-acc dur-acc)
+                                [(concat events-acc events)
                                  (+ dur-acc dur)])) 
                             [[] 0]
                             ms)
-          [:= & ms] :TODO
+          [:= & ms] (reduce (fn [[merged-events max-dur] m]
+                              (let [[events dur] (perf player-map
+                                                       context
+                                                       m)]
+                                [(merge-perfs merged-events events)
+                                 (max max-dur dur)]))
+                            [[] 0]
+                            ms)
           [:modify control m] :TODO)))
 
 (defn metro