[Class]
heap

Generates random permutations of its elements (sampling without replacement).

heap supports the following slot initializations:

:state random-state
Sets the random state object of the pattern to random-state. Defaults to *random-state*.

See generic pattern initializations for documentation on additional keyword initializations to the pattern.

Examples:

Example 1. The heap pattern. 

(define pat1 (new heap :keynums '(a4 b c5 d)))

(next pat1 #t)
⇒ (69 72 74 71)
(next pat1 #t)
⇒ (72 74 71 69)
(next pat1 #t)
⇒ (72 71 69 74)
(next pat1 #t)
⇒ (71 69 74 72)

Example 2. Two levels of heaps. 

(define pat1
  (new heap
       :of (list (new cycle :notes '(c4 cs d ef e f))
                 (new cycle :of (list (new heap :notes '(c3 cs d ef))
                                      (new heap :notes '(e3 f fs g))
                                      (new heap :notes '(gs3 a as b))))
                 (new cycle :notes '(fs2 g gs a as b)))))

(define (play-pat reps pat rate)
  (process repeat reps
           for k = (next pat)
           output (new midi :time (now) :keynum k
                       :duration (* rate 1.5))
           wait rate))

(events (play-pat 120 pat1 .1) "test.mid")
⇒ "test.mid"

See also: