Re: [ANN] Lua 5.4.0 (work1) now available

[albertmcchan <albertmcchan@...>]

On Mar 13, 2018, at 4:50 PM, Dirk Laurie <dirk.laurie@gmail.com> wrote:

> 2018-03-13 22:38 GMT+02:00 Rodrigo Azevedo <rodrigoams@gmail.com>:
> 
>> the (new) syntax could be extended to
>> non-tables
>> 
>> a = function(x) return x end
>> a = undef
> 
> This is perfectly legal if a is global, since a=undef is equivalent to
> _ENV.a = undef
> It is an error if a is local, or if a does not in fact currently have a value.
> 

Based on above example, local variable can not set to undef ?

Is this (new) syntax for performance ? (less memory churn ?)

I don't fully get it.
If user do not want "holes" in table, false can be used instead of nil
the feature seems just a new mapping (false -> nil, nil -> undef)

(I thought false were introduced for removing holes in table)