Example 1. Starting rts and sprouting from the REPL.

(define *pm*
  (portmidi-open :output 3 :latency 0))

(define (zzz len lb ub wai amp)
  (process repeat len
           output (new midi :time (now)
                       :duration .1 :amplitude amp
                       :keynum (between lb ub))
           wait wai))

(rts *pm*)
  
;;; eval to add stuff

(let ((k (between 20 100))
      (n (pick 3 5 7 11)))
  (sprout (zzz (* n (pick 2 3 4))
               k
               (+ k 7)
               (/ 1 n)
               .75)))

;;; stop when you are done.

(rts-stop)

Example 2. Endless Fluff. Stops only when rts-stop is called. (Todd Ingalls)

(define fluff '(60 62 64 67 72 65 69 48 50))

(define (endless-fluff num dur knums)
  (process repeat num for i from 0 
	   output
           (new midi :time (now) 
                :duration (* 2 dur)
                :amplitude .5
                :keynum (pickl fluff))
	   wait (pick dur (/ dur 2) (/ dur 4))
	   when (= i (1- num))
	   sprout (process repeat 4
                           output (new midi :time (now) 
                                       :duration 5
                                       :amplitude .5 
                                       :keynum (pickl knums)))
	   and
	   sprout (endless-fluff 20 1 knums)))

(rts *pm*)

(sprout (endless-fluff 20 1 fluff))

;;; stop when you are done.

(rts-stop)

Example 3. Sprouting into the scheduler from a receive hook.

(define *pm* (portmidi-open :input 1 :output 3 :latency 0))

(define (major-thirds len knum)
  (process with d = .1
           for i below len
           for k = (+ knum (* (mod i 5) 4))
           output (make-note-on 0 k 90) at (now)
           sprout (make-note-off 0 k 125) at (+ (now) .5)
           wait d))

(rts *pm*)

(set-receiver! (lambda (mm ms) ms
                 (if (note-on-p mm)
                   (sprout (major-thirds 20 (note-on-key mm)))))
               *pm*)

;;; stop receiving and scheduling.

(remove-receiver! *pm*)

(rts?)
⇒ :running

(rts-stop)

(rts?)
⇒ #f