(in-package :cm)
(in-syntax :midi)

;;;
;;; as the algorithm exeutes, the relative weight of the C,A,G,E notes
;;; change as a function of the algorithm's count, which
;;; ranges from 0 to length-1 of the algorithm. the variable prob holds 
;;; a probablility expression returning the relative weights of C,A,G,E.
;;; As the algorithm runs this expr is automatically evaluated whenever
;;; it is encountered in the random pattern. since random patterns
;;; recalculate probabilities once each period, the period length is set
;;; to 1 so that weights are recalculated on a per note basis. 
;;; the probabilities are expressed as an interpolation -- experiment
;;; with different weights  by changing interpolation coordinates.
;;;

(algorithm cage midi-note (length 200 amplitude .5)
  (vars (prob (expr (interpl count 0 .5 190 4))))
  (setf note 
    (item (notes (g3 weight prob)
                 (a  weight prob)
                 bf
                 (c4 weight prob)
                 d
                 (e  weight prob)
                 f
                 (r  max 1 weight .25)  ; pause every so often.
                 in random for 1)))
  (setf rhythm
    (item (rhythms 16 8 (rhythms 32 for 2) in random tempo 120)))
  (setf duration rhythm))