reset-pitch-sequence

reset a pitch-sequence on a specific pitch (lowest, highest, middle pitch of the sequence)

;;;; SUB


(defun center-position-in-list (list &key (get-value 'nil))
  (let ((pos))
    (progn
      (setf pos (if (evenp (length list))
                  (/ (length list) 2)
                  (/ (1+ (length list)) 2)))
      (if (equal get-value 'nil)
        (append pos)
        (nth (1- pos) list)))))


;;; MAIN

(defun reset-pitch-sequence (pitch-sequence pitch &key (type 'low))
  (let ((pitch1 (cond  ((equal type 'low)
                        (car (find-ambitus pitch-sequence :type :pitch)))
                       ((equal type 'high)
                        (cadr (find-ambitus pitch-sequence :type :pitch)))
                       ((equal type 'center) 
                        (center-position-in-list pitch-sequence :get-value t)))))
    (pitch-transpose (car (pitch-to-interval (list (if (chordp pitch1)
                                                     (car (pitch-melodize pitch1))
                                                     (append pitch1))
                                                   pitch))) pitch-sequence)))



(reset-pitch-sequence '(gs2 g2 a2 fs2 ds2 f2 e2) 'fs3 :type 'low)
=> (b3 bb3 c4 a3 fs3 gs3 g3)

(reset-pitch-sequence '(gs2 g2 a2 fs2 ds2 f2 e2) 'fs3 :type 'high)
=> (f3 e3 fs3 eb3 c3 d3 cs3)

(reset-pitch-sequence '(gs2 g2 a2 fs2 ds2 f2 e2) 'fs3 :type 'center)
=> (f3 e3 fs3 eb3 c3 d3 cs3)