elevator server: serve

-- pastebin: j1br869P

local side = "back"
local senderID = 0

local layout = {
  up = {
    name = "up",
    redstoneSide = "left",
    redstonePulses = 10
  },
  down = {
    name = "down",
    redstoneSide = "right",
    redstonePulses = 10
  }
}

-- helper functions

function directionOK(direction)
  for k,dir in pairs(layout) do
    if direction == dir.name then
      return true
    end
  end
  return false
end

function getLayout(direction)
  for key,value in pairs(layout) do
    if value.name == direction then
      return value
    end
  end
  return nil
end

-- main functions

function work(direction)

  if not directionOK(direction) then
    print("Invalid direction: " .. direction)
    return
  end

  print("Going " .. direction .. "...")

  local theLayout = getLayout(direction)

  if layout == nil then
    print("Something terrible happened...")
    return
  end

  local redpulseArgs = theLayout.redstoneSide .. " " .. tostring(theLayout.redstonePulses)

  shell.run("redpulse", redpulseArgs)

  print("Done!")
end

function repl()
  while true do
    print("Waiting for input from remote client...")
    local id, message = rednet.receive()
    if id == senderID then
      work(message)
    end
  end
end

function main()
  term.clear()
  term.setCursorPos(1, 1)

  rednet.open(side)
  repl()
  rednet.close(side)
end

main()