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1 files changed, 45 insertions, 0 deletions

diff --git a/src/main.clj b/src/main.clj
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+(ns main
+  (:require [missionary.core :as m]
+            [clojure.set :refer [difference]]))
+
+;; How many times per second are output continuous values sampled and turned
+;; into events?
+(def sample-rate (atom 1))
+
+;; Temporary atom to explore the concept of note state as a continuous value
+(def notes-on (atom #{}))
+(def >notes-on (m/signal (m/watch notes-on)))
+
+(defn play-note [v] (swap! notes-on conj v))
+
+(defn stop-note [v] (swap! notes-on disj v))
+
+(def clock
+  (m/ap
+   (loop []
+     (m/amb
+      (m/?
+       (m/sleep (/ 1000 @sample-rate)))
+      :tick
+      (recur)))))
+
+#_(play-note 1)
+#_(stop-note 1)
+
+;; convert the continuous time >notes-on flow to a series of discrete midi note on and off events
+(def output
+  (m/eduction (map (fn [{:keys [note-on note-off]}] {:note-on note-on :note-off note-off}))
+              (m/reductions (fn [{:keys [active note-on note-off]} [curr _]]
+                              {:note-on (difference (difference curr active) note-on)
+                               :note-off (difference (difference active curr) note-off)
+                               :active curr})
+                            #{}
+                            (m/sample
+                             vector
+                             >notes-on
+                             clock))))
+
+(def cancel
+  ((m/reduce prn output) {} {}))
+
+(cancel)