From 2a4fce4fef775f6661a625303de9b28b446f1877 Mon Sep 17 00:00:00 2001
From: Jake Zerrer <him@jakezerrer.com>
Date: Wed, 5 Nov 2025 15:32:14 -0500
Subject: Create keyboard function

---
 src/midi.clj    | 58 +++++++++++++++++++++++++++++++++++++++------------------
 src/scratch.clj | 31 +++---------------------------
 2 files changed, 43 insertions(+), 46 deletions(-)

(limited to 'src')

diff --git a/src/midi.clj b/src/midi.clj
index e63f811..330402b 100644
--- a/src/midi.clj
+++ b/src/midi.clj
@@ -233,32 +233,54 @@
   [>messages]
   (m/group-by #(.getChannel ^ShortMessage %) >messages))
 
+(defn |group-by-data-1
+  [>messages]
+  (m/group-by #(.getData1 ^ShortMessage %)
+              >messages))
+
+(defn |matching-commands
+  [>messages commands]
+  (m/eduction (filter (fn [^ShortMessage v]
+                        (contains? commands (.getCommand v)))) >messages))
+
 (def note-commands
   #{ShortMessage/NOTE_OFF
     ShortMessage/NOTE_ON
     ShortMessage/POLY_PRESSURE})
 
-(defn |notes
-  [>messages]
-  (m/group-by #(.getData1 ^ShortMessage %)
-              (m/ap
-               (let [^ShortMessage v (m/?> >messages)]
-                 (if (contains? note-commands (.getCommand v))
-                   v
-                   (m/amb))))))
-
 (def control-commands
   #{ShortMessage/CONTROL_CHANGE})
 
-;; TODO: |control-changes and |notes combine grouping and filtering, which isn't great
-(defn |control-changes
-  [>messages]
-  (m/group-by #(.getData1 ^ShortMessage %)
-              (m/ap
-               (let [^ShortMessage v (m/?> >messages)]
-                 (if (contains? control-commands (.getCommand v))
-                   v
-                   (m/amb))))))
+(defn keyboard
+  [f]
+  (m/ap
+    (let [[ch ch-messages]
+          (m/?> 128 (midi/|channels (midi/|short-messages (m/stream f))))
+          ch-messages (m/stream ch-messages)]
+      (m/amb=
+       (let [[note note-messages]
+             (m/?> 128 (-> ch-messages
+                           (midi/|matching-commands note-commands)
+                           (midi/|group-by-data-1)))]
+         [:key ch note
+          (m/?<
+           (m/relieve
+            (m/reductions
+             (fn [_prev curr]
+               (when (some? curr)
+                 (let [cmd (.getCommand ^ShortMessage curr)]
+                   (cond
+                     (= cmd ShortMessage/NOTE_ON)
+                     (.getData2 ^ShortMessage curr)
+                     (= cmd ShortMessage/POLY_PRESSURE)
+                     (.getData2 ^ShortMessage curr)
+                     (= cmd ShortMessage/NOTE_OFF)
+                     nil)))) nil note-messages)))])
+       (let [[control-number control-messages]
+             (m/?> 128 (-> ch-messages
+                           (midi/|matching-commands control-commands)
+                           (midi/|group-by-data-1)))]
+         [:control ch control-number (.getData2 ^ShortMessage (m/?< control-messages))])))))
 
 #_(defn >ch-stream [>device ch]
     (m/cp (m/?< (second (get >device ch)))))
diff --git a/src/scratch.clj b/src/scratch.clj
index 63d54a3..80baa83 100644
--- a/src/scratch.clj
+++ b/src/scratch.clj
@@ -1,41 +1,16 @@
 (ns scratch
   (:require [midi :refer [print-all-midi-devices >bus <bus] :as midi]
-            [missionary.core :as m])
-
-  (:import [javax.sound.midi ShortMessage]))
+            [missionary.core :as m]))
 
 #_(print-all-midi-devices)
 
 (def midi-keyboard  "CoreMIDI4J - Minilab3 MIDI")
 
 (def run
-  (<bus
-   midi-keyboard
-   (fn [f]
-     (m/ap
-       (let [[ch ch-messages]
-             (m/?> 128 (midi/|channels (midi/|short-messages (m/stream f))))
-             ch-messages (m/stream ch-messages)]
-         (println
-          (m/amb=
-           (let [[note note-messages] (m/?> 128 (midi/|notes ch-messages))]
-             [:key ch note
-              (m/?<
-               (m/relieve
-                (m/reductions
-                 (fn [_prev curr]
-                   (when (some? curr)
-                     (cond
-                       (= (.getCommand ^ShortMessage curr) ShortMessage/NOTE_ON)
-                       (.getData2 ^ShortMessage curr)
-                       (= (.getCommand ^ShortMessage curr) ShortMessage/POLY_PRESSURE)
-                       (.getData2 ^ShortMessage curr)
-                       (= (.getCommand ^ShortMessage curr) ShortMessage/NOTE_OFF)
-                       nil))) nil note-messages)))])
-           (let [[control-number control-messages] (m/?> 128 (midi/|control-changes ch-messages))]
-             [:control ch control-number (.getData2 ^ShortMessage (m/?< control-messages))]))))))))
+  (midi/<bus midi-keyboard midi/keyboard))
 
 (def cancel
   (run prn prn))
+
 (cancel)
 
-- 
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