Re: Quest: real world "Lua array with holes" usage

[Oliver Kroth <oliver.kroth@...>]

Hi

there is really a significant difference:

Whatever you assign to an array (or object) member in JavaScript, it 
stays in the array/object.
Assign null, or even undefined, doesn't matter; it's there and you can 
enumerate it.
You need to explicitly delete() it.

This is kind f confusing if you come from C++, in JavaScript delete() 
does not kill the data, it kills the variable; the data may be 
referenced else where and survive.
I do not really like the doubled feature undefined - null either.

--
Oliver


Am 21.07.2016 um 21:28 schrieb William Ahern:
> On Thu, Jul 21, 2016 at 12:13:40PM -0300, Rodrigo Azevedo wrote:
> > In face of recent (long) discussion about "Lua arrays", I would request a
> > simple few lines of real world examples where the use of "Lua arrays with
> > holes" is significant.
> The first use case that came to mind was JSON deserializers, where the
> obvious mapping of null to nil causes problems with arrays.
>
> But I think that's irritating mostly because superficially it _seems_ like
> such a trivial (and trivially fixable) mismatch between Lua and JavaScript
> type semantics, but as the thread has shown it's not trivial at all. I
> wouldn't use this case to argue for change in Lua.