Re: new "empty" value/type in Lua?

[Luis Carvalho <lexcarvalho@...>]

Coda Highland wrote:
> On Tue, Jul 2, 2013 at 5:34 PM, Luis Carvalho <lexcarvalho@gmail.com> wrote:
> >> Is something like this enough? (Note that 'n' is *not* hidden; I do
> >> not think hidden stuff is good in the end...)
> >
> > Agreed. I had a very similar version, but required that only integer keys can
> > be set in __newindex and setlength is implemented through __call:
> 
> --snip--
> 
> You didn't put in a way to shrink the array. Probably sufficient to
> handle calling newindex on n, I suppose.

No, since 'n' is an existent field (so newindex won't be called.) You can grow
the array by setting a[k] for k > t.n, but to really shrink -- that is, to set
t[k] = nil for k > n -- you have to use __call: a(n). That's just a matter of
taste, and it might be better to have an explicit setlength as in Roberto's
implementation, but I thought that shrinking the array would be rare and not
worth of a dedicated method (and setting __index.)

Cheers,
Luis

-- 
Computers are useless. They can only give you answers.
                -- Pablo Picasso

-- 
Luis Carvalho (Kozure)
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