Re: loadstring and accessing local variables

[Doug Rogers <doug.rogers@...>]

Gert wrote:
> * On 2009-12-11 Michal Kottman <k0mpjut0r@gmail.com> wrote  :
>> I have tried to achieve the same thing, and basically ended up
>> collectiong all the locals and upvalues using functions from debug
>> table, 
> Yes, I was afraid I would end up using the debug library. I just
> realized locals are not part of the environment - which would be my
> first intuitive guess - but live in registers instead.
> Ok, nothing I can do about it then, thanks for your help!

Well, if you know where you're loading the string then you might know
the local variables that are likely to be used by the loaded code. You
can put them in a table whose its metatable has an __index set to the
global table, like:

   var1 = "Hello"
   local function one()
      local var2 = "world"
      local code = "print(var1, var2)"
      chunk = loadstring(code)
      local locals = { var2 = var2, }
      setfenv(chunk, setmetatable(locals, { __index = _G }))
      chunk()
   end

   one()

But that would require a little bit of maintenance as the code changes.

Doug

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