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

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

	Hi Roberto

	Please, tell me what I've missed in that discussion:

> > In fact I don't quite understand what _ENV is.
> >
> > function f1()
> >   return f2()
> >     _ENV = {}
> >   end
> > end
> >
> > Would execution of f2 lead to a change in _ENV of f1? If _ENV is a
> > regular upvalue that may be shared, then it would.
>
> _ENV is a regular variable (and so a regular upvalue that may be
> shared). Then it does.
	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?

	Regards,
		Tomás