Re: The removal of function environments: An opportunity for optimization?

[Tomas Guisasola Gorham <tomas@...>]

	Hi Roberto

> > 	I thought it was a "regular local variable", since you defined:
> >
> > Any chunk is compiled as if surronded by the following code:
> > local _ENV = <some value>; function (...) <chunk> end
> >
> > 	Thus, I thought the above code (correcting `f2' to `function')
> > could be rewritten as:
> >
> > local _ENV = _ENV -- In Lua 5.1 it could be written `local _ENV = _G'
> > function f1()
> >   local _ENV = _ENV
> >   return function()
> >     _ENV = {}
> >   end
> > end
> >
> > 	In this case, I think the inner statement would not change f1's _ENV.
> > What am I missing?
>
> What gets the surrounding _ENV declaration are *chunks*, not functions.
> Everything inside the same chunk (a compilation unit) share the same
> _ENV, unless there are explicit declarations of other _ENVs.
	Sure.  However, the "body" of a function is a chunk isn't it?
I thought it should have a different (local) _ENV like the above code?

	Regards,
		Tomás

P.S.: Another function defined inside f1 would share the same upvalue
_ENV with the anonymous (f2) returned function and both could change
the local variable and affect the other:

local _ENV = _ENV -- In Lua 5.1 it could be written `local _ENV = _G'
function f1()
  local _ENV = _ENV
  function unused() _ENV = {} end
  return function()
    _ENV = {}
  end
end

	However I thought these inner functions would only have access
to the _value_ of the outer _ENV...