Re: [ANN] Lua 5.2.0 (beta-rc1) now available

[Roberto Ierusalimschy <roberto@...>]

> On Tue, Jun 14, 2011 at 12:35 PM, David Given <dg@cowlark.com> wrote:
> > @label: -- 0
> > do
> >  goto label
> >  do
> >    @label: -- 1
> >  end
> >  @label: -- 2
> > end
> >
> > Does the goto jump to 0, 1, 2, or is this a compilation error?
> 
> Using the experimental method, it goes to the first label. In fact,
> putting a 'goto label' in block 1 still goes to 0, which is a wee bit
> surprising.

It goes to label 2, does it not? Label 1 is not visible (inside a
block). Label 0 is shadowed by label 2, which is in the same block as
the goto.

Maybe it would be safer to be a compilation error, but this is tricky.
Consider the next, similar code:

do
  goto label
  do
    @label: -- 1
  end
  @label: -- 2
end
@label: -- 0

Now, when the compiler sees label 0, label 2 and label 1 are out of
scope, so it makes no sense to raise an error.

-- Roberto