Config API

-- allow for direct manipulation of the global environment of the calling script
local env = {}
setmetatable(env, {__index = _G})
setfenv(2, env)
setfenv(1, env)

local function getNumber(desc, default)
  local result = nil
  while result == nil do
    if default == nil then
      io.write("Enter "..desc..": ")
    else
      io.write("Enter "..desc.." ["..tostring(default).."] :")
    end
    result = io.read()
    if result == "" and default ~= nil then
      result = default
      break
    else
      result = tonumber(result)
    end
  end
  return result
end

local function load(fileName)
  local f = fs.open(fileName, "r")
  if f ~= nil then
    local data = f.readAll()
    f.close()
    return textutils.unserialize(data)
  end
end

local function save(fileName, data)
  local f = fs.open(fileName, "w")
  f.write(textutils.serialize(data))
  f.close()
end

config = {
  load = load,
  save = save,
  getNumber = getNumber
}