Re: A question about table's length

[steve donovan <steve.j.donovan@...>]

On Wed, Dec 30, 2009 at 12:05 PM, Philippe Lhoste <PhiLho@gmx.net> wrote:
> Perhaps the comment from ltable.c:

Which is a clear statement about the current implementation. All in
all, it's best to avoid holes. We could go to a lot of trouble to
handle holey arrays, but their behaviour is not fully determined.

BTW, Lua iterator sequences have the same problems with nil values,
since they end the iteration.

A map() function could easily generate lots of holes:

map(tonumber,{'10','x','20','y'})  --> {10,nil,20,nil}

I would suggest that the result here should actually be {10,20}, that
is, if the function called by map() returns nil, then it should not be
part of the result array.  We avoid holes, and get a convenient
filter-map idiom.

steve d.