Re: Let's not break existing scripts.

[Paul Hudson <phudson@...>]

Holy topic rehash, Robin.

Can we follow luiz's suggestion to drop this discussion?

On 10/11/2011, Petite Abeille <petite.abeille@gmail.com> wrote:
>
> On Nov 10, 2011, at 7:06 PM, Duncan Cross wrote:
>
>> No, no and no. :)
>
> Right, my bad :)
>
>> _ENV is only the first upvalue for a function that was compiled from a
>> top-level source code chunk. Functions *in general*, i.e. also
>> including functions defined inside a chunk or other function, may have
>> _ENV at a different position, or even not at all.
>>
>> This has been discussed before:
>> http://lua-users.org/lists/lua-l/2011-01/msg00377.html
>
> Yes, thanks for the pointer, got confused somewhere along the way :))
>
> FWIW, I use the following rendition of Sergey Rhozenko's original 5.2
> setfenv:
>
> http://dev.alt.textdrive.com/browser/HTTP/debugx.lua#L66
>
> function setfenv( aFunction, anEnvironment )
>     local aFunction = GetFunction( aFunction, 2 )
>
>     for anIndex, aName, aValue in UpValues( aFunction ) do
>         if aName == '_ENV' then
>             return upvaluejoin( aFunction, anIndex, function() return
> anEnvironment end, 1 )
>         end
>     end
>
>     error( 'No _ENV found for ' .. aFunction )
> end
>
> Aside from its reliance on debug info, is there anything else subtly broken
> in that function?
>
> Thanks!
>
>
>
>

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