ii-V-I example

src/music.clj

@@ -34,6 +34,21 @@
           {:duration 1/4, :pitch [:G 3]}
           {:duration 1/4, :pitch [:A 3]}]])
 
+;; TODO exercise 2.1 (ii-V-I function)
+;; this will involve being able to answer, "what pitch is n semitones above this one?"
+
+(def ii-V-I
+  (let [Dm [:= (note 1 [:D 4])
+               (note 1 [:F 4])
+               (note 1 [:A 4])]
+        Gmaj [:= (note 1 [:G 4])
+                 (note 1 [:B 4])
+                 (note 1 [:D 5])]
+        Cmaj [:= (note 2 [:C 4])
+                 (note 2 [:E 4])
+                 (note 2 [:G 4])]]
+    [:+ Dm Gmaj Cmaj]))
+
 (defn note [duration pitch]
   {:duration duration, :pitch pitch})