;;;ExtractTwoParts
(let ()
(define (delete-highest-notes)
  ;delete highest note of each chord
  (d-MoveToBeginning)
  (let loop () 
    (if (d-NextChord) 
	(begin 
	  (if (d-CursorToNote (d-GetNoteFromTop)) (d-StagedDelete))
	  (loop)))))

(define (delete-lower-notes)
  (d-MoveToBeginning)
  (let loop ((continue #f))
    (if (d-NextChord)
	(begin 
	  (if (d-CursorToNote (d-GetNoteFromTop 2))
	      (begin 
		(d-RemoveNoteFromChord)
		(set! continue #t)
		(loop continue))
	      (loop continue)))
	(if continue
	    (begin
	      (d-MoveToBeginning)
	      (loop  #f))))))
;;procedure starts here 

    (d-MoveToBeginning)
    (d-GoToEnd)
    (d-Copy)
    (d-MuteStaff)
    
    (d-AddAfter)
    (d-MuteStaff "unmute")   
    (d-NonPrintingStaff 'noninteractive)
    (d-Paste)
    (delete-lower-notes);;delete part 2 (and anything extra)

    (d-AddAfter)
    (d-MuteStaff "unmute")   
    (d-NonPrintingStaff 'noninteractive)
    (d-Paste)
    (delete-highest-notes);;delete part 1

    (d-SimplifyTies)
    (d-MoveToStaffUp)
    (d-SimplifyTies))