class Buffer
  -- number -> Buffer
  -- creates a new Buffer with the given limit number
  new: (limit = 5) =>
    @limit = limit -- number
    @data = {}     -- table

  -- nil
  -- clears all entries in @data if its length is above number @limit
  purge: =>
    if #@data > @limit
      table.remove @data, 1
      @purge!
    else return

  -- anything -> nil
  -- adds the given line anything to @data and calls the too long purging function
  add: (line) =>
    table.insert @data, line
    @purge!

with Buffer 5
  while true
    n = io.read!
    if n ~= nil
      \add n
    else
      break

  for _, i in pairs .data
    print i