Hi,

 

(setf test-flatten (flatten 
                   '((q a4 -e gs4 e4 -)
                    (q a4 e - e4 d4) 
                    (-e g4 e4 - q a4) 
                    (-h.) 
                    (-q e a4 gs4 - g4))))

(setf por (length-rest-position test-flatten)) 
==>(1 4 7 10 13 15 16 19)

  (setf sr (position-filter por test-flatten))
==>(-e - - -)
;should be this:
;  (-e - - - - -h. -q -e)
;or do I miss something?

Thanks for assistance!

(position-filter por (single-events test-flatten))
=> ((-e) (-e) (-e) (-e) (-e) (-h.) (-q) (-e))