I want to build a monophonic synthesizer and am failing miserably at last note priority logic. Ideally, I'd like to use only functions that also run on the Daisy Seed. Does anyone have any idea how this could work? The idea is that when I press two notes and release the second one, the first one should sound again. Ideally with retrigger, but that's for the future.

One way is just to keep a list of notes and only play the last one added to the list. When a key is released you have to iterate through the list and find that note, then remove it
(when the list becomes empty that's when you provide your note off for the last one)

Can you give me an example? I have no idea how to deal with lists. A list of 3 note will work for me.
I want to replace the [> 0] function:

it's way more complex than that and you need to keep track of things in a list or array

check [else/mono], maybe it helps

Tried to make an example, maybe could be simpler:
last_note_priority.pd
edit: removed some unnecessary routing logic

@Basalt idk what version of pd daisy uses but my example only uses pd vanilla objects
Most complex/newest object functions are in [list store]

thank you so much i will check it out next days:
This seems to be a much more complex issue than initially assumed. For now, I would be satisfied if the sound simply did not turn off when a note is released, even though another one is still pressed.

@Basalt well it has to have some way of remembering/storing which notes ore still pressed.. that's what the list does.
If you don't need it to go back to the still-held/playing pitch maybe you could get away with a counter, increment for note-ons and decrement for note-offs