如何使用 lua 脚本中的脚本重新启动 lua 程序

Question

又是我

我正在尝试用 Lua 制作一个终端程序，因为它是我所知道的最好的语言，我正在用它制作计算器程序，并且我正在尝试制作它，所以如果用户键入“exit”，程序将重启会回到终端，但是不知道怎么通过代码重置程序。如果有人能提供帮助，我们将不胜感激。

这是代码：

io.write("Terminal is starting up --- done!")
io.write("Making sure everything works --- Done!")
cmd = io.read()
io.write(">")

if cmd == "" then 
    io.write(">\n")
end

if cmd == "cal"then
    io.write("Calculator Terminal Program v1.0")
    io.write("what operation?/n")
    op = io.read()
    
    if op == "exit"then
        io.write("Exiting")
    end
end

Answer 1

你可能想要os.exit()，它会终止整个程序。

Answer 2

我认为这可以通过创造性地使用 load() 和协程来实现 当总共发生 3 个错误时，这将停止自行重启

if innerProgram == nil then --innerProgram will set to true when it load itself
  local filename = nil
  local errorLimit = 3 --Change this to any value to enable this code to restart itself when error occur until this amount of time set zero or below to exit instantly when error occur
  local errors = 0
  local filename = function()
    local str = debug.getinfo(2, "S").source:sub(2)
    return str:match("^.*/(.*)") or str
  end
  filename = filename()
  local src_h = io.open(filename, "r") --open in read mode
  local src = src_h:read("*a")
  src_h:close()
  local G = _G
  local quit = false --set true when you want to exit instead restart
  local code = nil
  local request = false
  local restart = false --set true when you want restart
  local program
  local yield = coroutine.yield --Incase when coroutine get removed in your calculator code for no reason
  local running = coroutine.running
  local exit = os.exit
  function G.restart()
    restart = true --Always refer to restart variable above
    request = true
    yield() --Always refer to yield above
  end
  function G.os.exit(exitcode) --Replace os.exit with this
    quit = true --Always refer to quit variable above
    reuqest = true
    code = exitcode or nil
    yield() --Always refer to yield above
  end
  function G.coroutine.yield()
    if running() == program and request == false then --Emulating coroutine.yield when it not run inside coroutine
      error("attempt to yield from outside a coroutine")
    end
  end
  G.innerProgram = true --So the inner program not keep loading itself forever
  function copy(obj, seen)
    if type(obj) ~= 'table' then return obj end --got from https://stackoverflow.com/questions/640642/how-do-you-copy-a-lua-table-by-value for us to clone _G variable without reference to original _G thus we can do total restart without using same _G
    if seen and seen[obj] then return seen[obj] end
    local s = seen or {}
    local res = setmetatable({}, getmetatable(obj))
    s[obj] = res
    for k, v in pairs(obj) do res[copy(k, s)] = copy(v, s) end
    return res
  end
  print("Loading "..filename)
  program = coroutine.create(load(src, filename, "bt", copy(G)))
  while errors < errorLimit do
    restart = false
    local status, err = coroutine.resume(program)

    if restart == true then
      print("Restarting...")
      program = coroutine.create(load(src, filename, "bt", copy(G)))
      --Put errors = errors + 1 if you want errors counter to reset every time the program request restart
    end
    
    if status == false and restart ~= true then
      print(filename.." errored with "..err.."\nRestarting...")
      program = coroutine.create(load(src, filename, "bt", copy(G)))
      errors = errors + 1
    elseif restart ~= true then
      print(filename.." done executing.")
      exit()
    end
  end
  return
else
  innerProgram = nil --Nil-ing the variable
end

特点

1. 总共出现 3 个错误时自动退出（配置 errorLimit 变量）
2. _G 未共享（与程序开头的_G 相同，但未与实际的_G 链接）
3. 在协程之外模拟让步
4. 替换了 os.exit 使其屈服，然后自加载器运行 os.exit

如何使用

将我上面给出的代码放在代码的第一行

功能编号 1 和 3 测试

a 内容出错，每次错误重启时值都会不同

if a == nil then --Only set a when a equal nil so if _G was shared the error value will be same 
  a = math.random() --Set global a to a random value
end
error(a) --Error with number a
os.exit()

Answer 3

要直接回答您的问题，我不认为可以“重新启动程序”。但是，通过利用loops，您可以获得相同的结果。

例如，此代码可能会执行您想要的操作：

print('Terminal is starting up --- done!')
print('Making sure everything works --- Done!')

repeat
    io.write('>')
    cmd = io.read()

    if cmd == 'cal' then
        print('Calculator Terminal Program v1.0')
        repeat
            io.write('Operation: ')
            op = io.read()
        until op == 'exit'
        print('Exiting')
    elseif cmd == 'command' then
        --another command
    else
        print('Unknown command.')
    end

until cmd == 'exit'

其他提示：

• 您应该利用elseif 而不是编写多个单独的if 语句来提高可读性。
• 如果您在编写一些文本后想要换行以获得更好的终端体验，请考虑使用print 函数。你也可以使用io.write('\n')。