(defun replace-lengths-of-a-pitch-sequence (omn-list pitch-list length-list) (flatten (loop with cnt = 0 for i in (single-events omn-list) when (equal (cadr i) (nth cnt pitch-list)) collect (append (list (nth cnt length-list)) (rest i)) and do (incf cnt) else collect i when (= cnt (length pitch-list)) do (setf cnt 0)))) (setf white-series-l (vector-to-pitch '(c4 c5) (gen-white-noise 100 :type :logistic :seed 23))) (replace-lengths-of-a-pitch-sequence (cons 't white-series-l) '(e4 f4 a4 gs4 g4 b4 c5 bb4) '(2/16 3/16 4/16 5/16 6/16 7/16 8/16)) => '(t gs4 mf t g4 mf t g4 mf t c5 mf t g4 mf t gs4 mf 1/8 e4 mf 3/16 f4 mf t gs4 mf t gs4 mf t bb4 mf t gs4 mf t fs4 mf t fs4 mf t f4 mf t g4 mf t bb4 mf t b4 mf t b4 mf t g4 mf t e4 mf t g4 mf t fs4 mf t b4 mf 1/4 a4 mf t g4 mf t g4 mf t a4 mf t b4 mf t fs4 mf t bb4 mf t a4 mf 5/16 gs4 mf t a4 mf 3/8 g4 mf t a4 mf t a4 mf t a4 mf t a4 mf t a4 mf t f4 mf t bb4 mf t g4 mf t fs4 mf 7/16 b4 mf t a4 mf t g4 mf t bb4 mf t a4 mf t gs4 mf t a4 mf t gs4 mf t g4 mf t g4 mf t gs4 mf t a4 mf t f4 mf t f4 mf t bb4 mf t gs4 mf t fs4 mf t a4 mf t g4 mf t a4 mf t g4 mf t gs4 mf t bb4 mf t eb4 mf t bb4 mf t fs4 mf t fs4 mf t gs4 mf t g4 mf t gs4 mf t gs4 mf t c4 mf t gs4 mf t g4 mf t gs4 mf 1/2 c5 mf bb4 mf t gs4 mf t fs4 mf t fs4 mf t bb4 mf t a4 mf t g4 mf t g4 mf t b4 mf t g4 mf t f4 mf t g4 mf t gs4 mf t gs4 mf t gs4 mf t gs4 mf t fs4 mf t gs4 mf t eb4 mf t a4 mf)  

here is a function that can be used for "post-..." of an OMN score...
you could INSERT a sequence by BAR/BEAT (a slightly modified variant of OVERWRITE), so you can 
place your insert exactly!
 
greetings
andré
 
;;; INSERTING (defun get-resolution2 (be) (cond ((member (cadr be) '(3 6 12 24 48)) 1/24) ((member (cadr be) '(1 2 4 8 16 32)) 1/16) ((member (cadr be) '(5 10 20 40)) 1/20) ((member (cadr be) '(7 14 28 56 1)) 1/28))) (defun insert (seq &key insert bar/beat) (car (last (let ((bar) (beat) (resolution) (distance)) (progn (setf bar (loop for i in bar/beat collect (car i)) beat (loop for j in bar/beat collect (cadr j))) (loop for ba in bar for be in beat for ins in insert with time-sign = (get-time-signature seq) with ord-time-sign = (get-time-signature seq) ;with ins-rounded = '(0) with ins-add = '(0) do (setf resolution (get-resolution2 be) time-sign (if (listp (car time-sign)) (loop for i in time-sign when (> (caddr i) 1) append (loop repeat (caddr i) collect (list (car i) (cadr i))) else collect (list (car i) (cadr i))) (append time-sign)) distance (if (listp (car time-sign)) (+ (sum (loop repeat (- ba 1) for i in time-sign collect (/ (/ (car i) (cadr i)) (get-resolution2 be)))) (/ (/ (1- (car be)) (cadr be)) (get-resolution2 be)) ;;; ins-rounded add (/ (get-span (flatten ins-add)) (get-resolution2 be)) ) (+ (/ (* (1- ba) (/ (car time-sign) (cadr time-sign))) (get-resolution2 be)) (/ (/ (1- (car be)) (cadr be)) (get-resolution2 be)) ;;; ins-rounded add (/ (get-span (flatten ins-add)) (get-resolution2 be))) )) do (setf seq (omn-to-time-signature (length-rest-merge (flatten (loop repeat (length (omn-to-time-signature seq (list (numerator resolution) (denominator resolution)))) for cnt = 0 then (incf cnt) with new-seq = (omn-to-time-signature seq (list (numerator resolution) (denominator resolution))) with ins-rounded = (append ins (rest (length-rational-quantize (list (apply '+ (mapcar 'abs (omn :length ins)))) :round resolution))) when (= cnt distance) collect ins-rounded and do (setf ins-add (append ins-rounded ins-add)) else collect (nth cnt new-seq)))) ord-time-sign)) do (setf time-sign ord-time-sign) collect (omn-merge-ties seq))))))) ;;; EXAMPLES: ;;; with changing time-signatures (insert '((e c6 a5 h b5 q tie) (q b5 b5 a5 tie) (q a5 q a5) (h. g5)) :insert '((-3q 3q c5 b4 bb4 a4) (-3q 3q c4 b3 bb3 a3)) ;;; bar numbers has to be in ascending order! :bar/beat '((1 (1 12)) (3 (1 12)))) (insert '((e c6 a5 h b5 q tie) (q b5 b5 a5 tie) (q a5 q a5) (h. g5)) :insert '((-2/12)) :bar/beat '((2 (2 12)))) ;;; with constant time-signature (insert '((e c6 a5 h b5 tie) (q b5 b5 a5 tie) (h a5 q a5) (h. g5)) :insert '((3q c5 b4 bb4 a4) (-3q 3q c4 b3 bb3 a3)) ;;; bar numbers has to be in ascending order! :bar/beat '((1 (7 12)) (3 (2 12)))) (insert '((e c6 a5 h b5 tie) (q b5 b5 a5 tie) (h a5 q a5) (h. g5)) :insert '((-h.)) :bar/beat '((2 (1 4))))  

i think, it works like that :-)
 
now, you could OVERWRITE you original OMN sequentially with inserts... (it's very useful for "post-production" of your generated score!). 
i have changed the input-format (bar/beat), and it also works with changing time-signatures... i know, janusz or the opmp-programmers could code it smarter, but my concept/code seems to work... so take it and optimize it!!!
 
greetings
andré
p.s. when wil be approx. the release of vers 2 of OPMO?
 
;;; OVERWRITING (defun get-resolution2 (be) (cond ((member (cadr be) '(3 6 12 24 48)) 1/24) ((member (cadr be) '(1 2 4 8 16 32)) 1/16) ((member (cadr be) '(5 10 20 40)) 1/20) ((member (cadr be) '(7 14 28 56 1)) 1/28))) (defun overwrite (seq &key insert bar/beat) (car (last (let ((bar) (beat) (resolution) (distance)) (progn (setf bar (loop for i in bar/beat collect (car i)) beat (loop for j in bar/beat collect (cadr j))) (loop for ba in bar for be in beat for ins in insert with time-sign = (get-time-signature seq) with ord-time-sign = (get-time-signature seq) do (setf resolution (get-resolution2 be) time-sign (if (listp (car time-sign)) (loop for i in time-sign when (> (caddr i) 1) append (loop repeat (caddr i) collect (list (car i) (cadr i))) else collect (list (car i) (cadr i))) (append time-sign)) distance (if (listp (car time-sign)) (+ (sum (loop repeat (- ba 1) for i in time-sign collect (/ (/ (car i) (cadr i)) (get-resolution2 be)))) (/ (/ (1- (car be)) (cadr be)) (get-resolution2 be))) (+ (/ (* (1- ba) (/ (car time-sign) (cadr time-sign))) (get-resolution2 be)) (/ (/ (1- (car be)) (cadr be)) (get-resolution2 be))))) do (setf seq (omn-to-time-signature (length-rest-merge (omn-merge-ties (flatten (loop repeat (length (omn-to-time-signature seq (list (numerator resolution) (denominator resolution)))) for cnt = 0 then (incf cnt) with new-seq = (omn-to-time-signature seq (list (numerator resolution) (denominator resolution))) with ins-rounded = (append ins (rest (length-rational-quantize (list (apply '+ (omn :length ins))) :round resolution))) when (= cnt distance) collect ins-rounded and do (setf cnt (+ (/ (get-span (flatten ins-rounded)) resolution) cnt -1)) else collect (nth cnt new-seq))))) ord-time-sign)) do (setf time-sign ord-time-sign) collect seq)))))) ;;; EXAMPLES: ;;; with changing time-signatures (overwrite '((e c6 a5 h b5 q tie) (q b5 b5 a5 tie) (q a5 q a5) (h. g5)) :insert '((3q c5 b4 bb4 a4) (3q c4 b3 bb3 a3)) :bar/beat '((1 (2 12)) (3 (1 12)))) ;;; with constant time-signature (overwrite '((e c6 a5 h b5 tie) (q b5 b5 a5 tie) (h a5 q a5) (h. g5)) :insert '((3q c5 b4 bb4 a4) (3q c4 b3 bb3 a3)) :bar/beat '((1 (7 12)) (3 (2 12))))