Re: Struggling with _ENV in Lua 5.2

[Daurnimator <quae@...>]

2011/11/11 Procházka Lukáš Ing. - Pontex s. r. o. <LPr@pontex.cz>:
> Hello,
>
> I have the following problem with Lua 5.2 build on Windows, MSVC 2008:
>
> ----
> Lua 5.2.0 (beta)  Copyright (C) 1994-2011 Lua.org, PUC-Rio
>>
>> local t = {x=10,y=20}
>> local f1
>> do local _ENV=t
>>>
>>>  function f1()
>>>    return x+y
>>>  end
>>> end
>
> stdin:2: attempt to index local '_ENV' (a nil value)
> stack traceback:
>         stdin:2: in main chunk
>         [C]: in ?
>>
>> print(f1())
>
> stdin:1: attempt to call global 'f1' (a nil value)
> stack traceback:
>         stdin:1: in main chunk
>         [C]: in ?
> ----
>
> Why? What am I doing wrong?
>
> I build the Lua interpreter from downloaded lua-5.2.0-beta source files via
> MSVC 2008; I just created an empty Win console project and I added all
> source files in it; luac.c must have been excluded from the build as it
> defines another main() (gives Lua compiler).
>
> If you are familiar with MSVC, you can try the project from
> http://www.filejumbo.com/Download/A3C039305593C10D - just to check whether
> you will get the same behaviour.
>
> BTW: I didn't find any Lua-5.2-for-Windows build/installer, so that's why I
> built Lua.exe myself.
>
> BTW2: The whole discussion on "Struggling with _ENV in Lua 5.2" can be found
> at
> http://forum.luahub.com/index.php?topic=3330.msg7649#msg7649
> .
>
> LuP
>
>
> NB: I sent this mail yesterday, but I probably was not subscribed to this
> mailing list yet; I apologize if I was and this mail is duplicated so.
>
> --
> Ing. Lukáš Procházka [mailto:LPr@pontex.cz]
> Pontex s. r. o.      [mailto:pontex@pontex.cz] [http://www.pontex.cz]
> Bezová 1658
> 147 14 Praha 4
>
> Tel: +420 244 062 238
> Fax: +420 244 461 038
>
>
>

In the interpreter each line is a chunk,
i.e. locals only last for the line they are on.