delete events while maintaining other start-times?

[Rick Taube]

this function will delete and expunge muted objects and update times in the
remaining objects. you need to install the mute.lisp patch before using.

(defun flush-muted (thread &aux last)
  (run-object thread 0)
  (map-object #'(lambda (o)
                  (if (mutedp o) (delete-object o)
                    (if last
                      (setf (object-rhythm last)
                            (- (object-time o) (object-time last))
                            last o)
                      (setf last o))))
              thread)
  (expunge-object thread)
  thread)

;;;-------------

Stella [Top-Level]: tlist aaa 0
Aaa
    0.00    1. #<MIDI-NOTE | 60|     1|     1| 64| 0|>
    1.00    2. #<MIDI-NOTE | 61|     1|     1| 64| 0|>
    2.00    3. #<MIDI-NOTE | 62|     1|     1| 64| 0|>
    3.00    4. #<MIDI-NOTE | 63|     1|     1| 64| 0|>
    4.00    5. #<MIDI-NOTE | 64|     1|     1| 64| 0|>
    5.00    6. #<MIDI-NOTE | 65|     1|     1| 64| 0|>
    6.00    7. #<MIDI-NOTE | 66|     1|     1| 64| 0|>
    7.00    8. #<MIDI-NOTE | 67|     1|     1| 64| 0|>
    8.00    9. #<MIDI-NOTE | 68|     1|     1| 64| 0|>
    9.00   10. #<MIDI-NOTE | 69|     1|     1| 64| 0|>

Stella [Top-Level]: map aaa[::2] mute $

Stella [Top-Level]: (flush-muted #!aaa)
#<THREAD: Aaa>
Stella [Top-Level]: tlist aaa 0
Aaa
    0.00    1. #<MIDI-NOTE | 61|     2|     2| 64| 0|>
    2.00    2. #<MIDI-NOTE | 63|     2|     2| 64| 0|>
    4.00    3. #<MIDI-NOTE | 65|     2|     2| 64| 0|>
    6.00    4. #<MIDI-NOTE | 67|     2|     2| 64| 0|>
    8.00    5. #<MIDI-NOTE | 69|     1|     1| 64| 0|>

Stella [Top-Level]: