startup.lua

print("init")
sleep(os.clock()<2 and 2 or 0)
print("run")

local mobType = "Zombie"

settings.load("guestbook")
local guestbook = settings.get("guestbook",{})

local p = peripheral.wrap("right")

local w,h = term.getSize()

local book = window.create(
    term.current(),
    1, 1,
    w, h-4,
    true
)

local output = window.create(
    term.current(),
    1,h-4,
    w,4,
    true
)

local function scan()
    for i,mob in ipairs(p.sense()) do
        if mob.name == mobType
        and not guestbook[mob.id]
        and mob.y == 0
        and mob.x >= 1 and mob.x <= 2
        and mob.z >= 1 and mob.z <= 2
        then
            local old = term.redirect(output)
            term.setTextColor(colors.lightGray)
            print("New mob", mob.name, mob.displayName)
            print(mob.id)
            term.redirect(old)
            guestbook[mob.id] = string.format("day %s, at %s", os.day(), os.time())
            settings.set("guestbook", guestbook)
            settings.save("guestbook")
        end
    end
end

local function display()
    local old = term.redirect(book)
    term.setBackgroundColor(colors.white)
    term.setCursorPos(1,1)
    term.clear()
    for id,date in pairs(guestbook) do
        term.setTextColor(colors.gray)
        print(id)
        term.setTextColor(colors.black)
        print(date)
        term.setTextColour(colors.lightGray)
        print(" "..string.rep("-",w-2))
    end
    term.redirect(old)
end
repeat
    scan()
    display()
    book.redraw()
    output.redraw()
    sleep(20)
until false