for-loop - Lua - 在 for 循环中更改 'stop' 变量的值，它还会正常终止吗？

Question

例如，如果我执行以下操作:

local iStop = 32
for i = 1, iStop do
  iStop = iStop + 1
end

循环是否保证只运行 32 次迭代，还是有可能无限运行？

Answer 1

请引用Lua Reference Manual 3.3.5: For statement

 for v = e1, e2, e3 do block end

is equivalent to the code:

 do
   local var, limit, step = tonumber(e1), tonumber(e2), tonumber(e3)
   if not (var and limit and step) then error() end
   var = var - step
   while true do
     var = var + step
     if (step >= 0 and var > limit) or (step < 0 and var < limit) then
       break
     end
     local v = var
     block
   end
 end

...

All three control expressions are evaluated only once, before the loop starts.

循环将运行 32 次。实际的循环限制是循环开始前 iStop 值的副本，无论您在循环中对 iStop 执行什么操作，都不会影响循环限制。