Send bang on track change - "Setting the Id cannot be triggered by notifications. you will need to defer your response"

[agent314]

I have created a device that allows a MIDI-mappable dial to be used to trigger clips on its respective track.

It gets the current track number, counts the number of clips in that track, then uses that value to set the number of clips to trigger, interpolating/scaling the MIDI input value to match the number of clips.

The problem I am running into is that whenever I add a new track or move the track containing the device, the track number changes and I have to manually retrigger the find-the-track-number code path with a button.

This feels like it should be trivial to implement using [live.observer] with [live.path live_set tracks] to send a bang to the code path that sets the track number to the current track (rather than do it manually with a button), but I am running into the "you will need to defer your response" issue and cannot seem to get live.observer working, no matter how many [deferlow] objects I add to my path.

Is there no way to send a single bang message when adding/changing tracks, or is there a non-obvious way to accomplish this that I simply haven't found?

[agent314]

As soon as I posted this I had the idea, "why not just trigger the code path to choose the track every time the dial changes?"

I updated that to send the bang, and it appears to be working as expected, but it feels wasteful to recalculate that value every time I move the dial.

Is that something I shouldn't worry about since the performance cost is relatively trivial, or is it worthwhile to try to find a solution using an event notification whenever the tracks update, to save on performance?

[chapelier fou]

If you don't mind sharing the patch, I'd be happy to take a look and see if I can help.

Cheers.