Implement pitch and trans

src/music.clj

@@ -72,11 +72,16 @@
   "Returns the absolute pitch of a pitch class at an octave"
   (+ (* 12 octave) (pc-to-int pitch-class)))
 
-;; TODO
 (defn pitch [abs-pitch]
   "Returns the pitch class and octave represented by the absolute pitch.
    In cases of enharmonic equivalence, returns the sharp rather than the flat."
-  ())
+  (let [scale [:C :C# :D :D# :E :F :F# :G :G# :A :A# :B]
+        octave (quot abs-pitch 12)
+        index (rem abs-pitch 12)]
+    [(nth scale index) octave]))
+
+(defn trans [n [pitch-class octave]]
+  (pitch (+ (abs-pitch pitch-class octave) n)))
 
 ;; TODO exercise 2.1 (ii-V-I function)
 ;; this will involve being able to answer, "what pitch is n semitones above this one?"