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- Subject: RE: Closures
- From: "Bilyk, Alex" <ABilyk@...>
- Date: Thu, 13 May 2004 12:08:59 -0700
Would this change from Lua 5.1 apply to "for k,v
in <function> do end" and other variations of 'for'
as well or just to the version with numeric limits?
Thanks,
Alex
Jack Christensen
preguntó:
> I'm getting some results I
was not expecting with this code.
> functionList = {}
> for
i=1, 10 do
> functionList[ i ] = function()
> print( i )
>
end
> end
> for i=1, 10 do
> functionList[ i
]()
> end
> I get ten 10's printed out. As I understand
closures I would have
> expected 1 to 10. Could someone enlighten me as
to what is wrong?
I agree. Fortunately,
this odd behaviour is slated to change
in Lua
5.1. (see below)
There is nothing wrong
with your understanding of closures. It is
the implementation of the "for" loop which you have gotten
wrong;
in effect, the loop is:
local i = 1
while i < 10 do
...
i = i +
1
end
As opposed to:
local
_control_ = 1
while _control_ < 10
do
local i =
_control_
...
_control_ = _control_ + 1
end
------> results from Lua 5.1 ----->
Lua 5.1 (work) Copyright (C) 1994-2004 Tecgraf,
PUC-Rio
> functionList = {}
> for i = 1, 10 do
>> functionList[i] = function() print(i) end
>> end
> for i = 1, 10 do functionList[i]() end
1
2
3
4
5
6
7
8
9
10
>
