Re: Replacement for unlocked refs?

["J. Perkins" <jason@...>]

Keeping all references in the weak table is a good idea, I will
do that. Still, I stand by my assertion that this is a critical
function of an embedded language which should be a part of the
library, not "emulated" in user code. But since I seem to be the
only one concerned by it, I will go suffer in silence  ;)

Thanks for the help,

Jason



Roberto Ierusalimschy wrote:

> On Thu, 31 Jan 2002, J. Perkins wrote:
>
>
> > But really two tables are required, right? One for locked refs
> > and another for unlocked? And then the reference value must also
> > indicate which table it is stored in, [...]
>
> Usually you know whether a reference points to a locked or unlocked object,
> so it does not need to include that information.
>
> (If you really want to emulate the old behavior, you can use two tables,
> one weak and one strong. You put all elements in the weak table,
> but only locked ones go to the other table. That way, your references
> are always to the weak table; you do not need negative indices. To unref,
> you set the ref to nil in both tables. But, as I said, I think most
> people don't need that.)
>
>
>
>
> > Is there some reason why unlocked refs were dropped?
>
> It was replaced by weak references (and, unlike some other languages, we
> do not need more than one way to do something ;-). But also the whole
> system of references was somewhat outdated by multiple states. And there
> is a tendency in Lua to unificate all data structures into tables.
> Globals went to tables, now tag methods and references are going, too.
>
> -- Roberto