Sketch of symbolic composition of sound operations

symbolic_composition.clj

(defn ->op
  "Create an operation that just samples that sound
  without additional processing."
  [s]
  (let [s* (gensym "sound")]
   `{:bindings {~s* ~s}
     :duration (.duration ~s*)
     :channels (.channels ~s*)
     :amplitude (.amplitude ~s* ~'t ~'c)}))


(->op '(read-sound "foo.wav"))

;=>
{:duration (.duration sound7679)
 :bindings {sound7679 (read-sound "foo.wav")}
 :amplitude (.amplitude sound7679 t c)
 :channels (.channels sound7679)}

(defn gain-op [gain op]
  (update-in op [:amplitude]
             (fn [e] `(* ~gain ~e))))

(gain-op 0.5 (->op '(read-sound "foo.wav")))

;=>
{:duration (.duration sound7697),
 :bindings {sound7697 (read-sound "foo.wav")},
 :amplitude (clojure.core/* 0.5 (.amplitude sound7697 t c)),
 :channels (.channels sound7697)}


(defn multiply-op [op1 op2]
  {:bindings (merge (:bindings op1) (:bindings op2))
   :duration `(max ~(:duration op1) ~(:duration op2))
   :channels `(.channels s1)
   :amplitude `(* ~(:amplitude op1) ~(:amplitude op2))})


(multiply-op (gain-op 0.5 (->op 's1)) (->op 's2))

;=>

{:bindings {sound7727 s1, sound7728 s2},
 :duration
 (clojure.core/max (.duration sound7727) (.duration sound7728)),
 :channels (.channels user/s1),
 :amplitude
 (clojure.core/*
  (clojure.core/* 0.5 (.amplitude sound7727 t c))
  (.amplitude sound7728 t c))}

;; Now we just need something to take an operation and compile it into
;; a sound.
;; E.g.
(compile (multiply-op (->op (read-sound "hi.wav"))
                      (->op s2)))

;=>
(let [s1 (read-sound "hi.wav")]
  (sound (max (.duration s1) (.duration s2))
         (fn [t c] (* (.amplitude s1 c) (.amplitude s2 c)))
         (.channels s1))))