example midi matrix

midimatrix.lua

box = {} -- a table of boxes

msg =
{
    ["cc"] = {"cc","val","ch"}
  , ["note_on"] = {"note","vel","ch"}
  , ["note_off"] = {"note","vel","ch"}
  , ["key_pressure"] = {"note","val","ch"}
  , ["pitchbend"] = {"val","ch",nil}
  , ["channel_pressure"] = {"val","ch",nil}
}

for source = 1,4 do -- I have four boxes (four USB MIDI ports)
  box[source] = midi.connect(source) -- box 1 == whatever's connected to port 1, etc
  box[source].connected = {false,false,false,false} -- all boxes are disconnected
  box[source].event = function(data) -- what to do when a box sends MIDI into norns:
    -- print("box "..source..":") -- uncomment this line to print which box, if you want
    local received = midi.to_msg(data) -- capture the message...
    -- tab.print(received) -- uncomment this line to print the message, if you want
    for destination = 1,4 do -- for each of the potential inter-box destinations:
      if box[source].connected[destination] then -- if the source is connected to a destination...
        local msg_1 = received[msg[received.type][1]] -- shorten message 1...
        local msg_2 = received[msg[received.type][2]] -- shorten message 2...
        local msg_3 = received[msg[received.type][3]] -- shorten message 3...
        -- send the source's messages to the destination box:
        box[destination][received.type](box[destination],msg_1,msg_2,msg_3)
        -- ^^ nb: I removed syntactic sugar from self:functionName() ^^
      end
    end
  end
end

function manage(src,dest,state) -- easier way to manage states:
  box[src].connected[dest] = state
  --`manage(2,1,true)` sets box 2 as source and box 1 as destination
  --`manage(2,1,false)` breaks the sending connection between box 2 and box 1
end