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

[David Given <dg@...>]

steve donovan wrote:
> On Mon, Jun 13, 2011 at 9:51 PM, Petite Abeille
> <petite.abeille@gmail.com> wrote:
>> Goto? Really? How quaint :P
> 
> Seriously, very useful sometimes.  Even the person who hammered
> structured programming into me using Pascal (Judy Bishop) accepted
> that a goto could be used without committing a sin.

Hell yeah. I'm really happy to see this, it's something I've been
wanting in Lua for ages...

> Also, interesting possibilities for code generation.

...primarily for this reason. Trying to flatten a basic block graph into
runnable code when all you have are if...then...else, while...,
repeat...until etc is *really hard*, and I believe (though I haven't
seen proof) is actually impossible in the general case. Having actual
goto available makes life so much easier.

I assume that goto labels exist in their own namespace and are scoped
alongside locals; but the necessity for forward references does make
life more complicated. e.g.:

@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?

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