在整个文件的闭包中看不到局部变量? [英] local variable cannot be seen in a closure across the file?

问题描述

假设我有以下两个Lua文件:

Suppose I have the following two Lua files:

在a.lua中:

local x = 5
f = dofile'b.lua'
f()

在b.lua中:

local fun = function()
  print(x)
end
return fun

然后，如果我在shell中运行luajit a.lua，它会显示nil，因为在b.lua定义的函数中看不到x.预期的打印应为5.但是，如果我将所有内容都放在一个文件中，那正是我想要的:

Then if I run luajit a.lua in shell it prints nil since x cannot be seen in the function defined in b.lua. The expected printing should be 5. However if I put everything in a single file then it's exactly what I want:

在aa.lua中:

local x = 5
local f = function()
  print(x)
end
f()

运行luajit aa.lua，它会显示5.

那么为什么在第一种情况下看不到x?

So why x cannot be seen in the first case?

推荐答案

顾名思义，局部变量对于块而言是局部的.

As their name suggests, local variables are local to the chunk.

dofile()从另一个文件加载块.由于它是另一个块，因此第一个块中的局部变量x未被它看到是有道理的.

dofile() loads the chunk from another file. Since it's another chunk, it makes sense that the local variable x in the first chunk isn't seen by it.

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