“Toggle” mode for note playback?

[misohoza]

You could try something like this:

noteIds = {}

function onNote(e)
	if noteIds[e.note] then
		releaseVoice(noteIds[e.note])
		noteIds[e.note] = nil
	else
		noteIds[e.note] = playNote(e.note, e.velocity, 0)
	end
end

function onRelease(e)
	-- do nothing
end