View difference between Paste ID: mg8cdQ9B and ULg3zm7N

 local mon = peripheral.find("monitor")
 local xMax, yMax = mon.getSize()
 
 os.loadAPI("radar")
 os.loadAPI("button")
 rednet.open("top")
 local roomLeft = "2"
 local roomRight = "4"
 
 local roomData = {[roomLeft] = "",
                   [roomRight] = ""}
 local bundleSide = "right"
 
 function fillButtons()
     button.setTable(roomLeft, openLeftDoor, 1, 1, 2, 2)
     button.setTable(roomRight, openRightDoor, xMax, xMax, 2, 2)
 end
 
 function load()
     if not fs.exists("roomdata") then
         return
     end
     local file = fs.open("roomdata", "r")
     local data = textutils.unserialize(file.readAll())
     roomData = data
     file.close()
     print("loading room data")
 end
 
 function save()
     local file = fs.open("roomdata", "w")
     file.write(textutils.serialize(roomData))
     file.close()
     print("save data")
 end
 
 function waitForInstruction()
     id, msg = rednet.receive("hotel")
     print(msg["room"] .. " " .. msg["player"])
 
     if msg["room"] == roomLeft then
         if msg["command"] == "checkin" then
             roomData[roomLeft] = msg["player"]
         elseif msg["command"] == "checkout" then
             roomData[roomLeft] = ""
         end
         save()
     end
 
     if msg["room"] == roomRight then
         if msg["command"] == "checkin" then
             roomData[roomRight] = msg["player"]
         elseif msg["command"] == "checkout" then
             roomData[roomRight] = ""
         end
         save()
     end
 
     waitForInstruction()
 end
 
 function openRightDoor()
     if radar.findClosest() == roomData[roomRight] then
         redstone.setBundledOutput(bundleSide, colors.blue)
         sleep(3)
         redstone.setBundledOutput(bundleSide, 0)
     end
 end
 
 function openLeftDoor()
     if radar.findClosest() == roomData[roomLeft] then
         redstone.setBundledOutput(bundleSide, colors.white)
         sleep(3)
         redstone.setBundledOutput(bundleSide, 0)
     end
 end
 
 function checkClick()
     event, side, x, y = os.pullEvent("monitor_touch")
     button.checkxy(x,y)
 end
 
 --button.heading("ROOMS")
 
 load()
 rednet.open("top")
 
 mon.clear()
 mon.setCursorPos(1, 1)
 
 button.heading("ROOMS")
 fillButtons()
 button.screen()
 
 function run()
     while true do
         checkClick()
     end
 end
 --waitForInstruction()
 parallel.waitForAll(run, waitForInstruction)