Re: Lua, LuaJIT2 and differences with the length operator

[Norbert Kiesel <nkiesel@...>]

On Tue, 2011-01-04 at 13:18 -0500, Greg Falcon wrote: 
> On Tue, Jan 4, 2011 at 1:02 PM, Leo Razoumov <slonik.az@gmail.com> wrote:
> > I am fine with the way #t operator is defined. It is logical and
> > consistent. My problem is different. I cannot see a good way to tell
> > when it is safe to trust #t and when not (longing for table.has_holes
> > test)
> 
> The only way to test if a table has holes is to walk it.  So if you
> just want to know if you can trust the answer of #t, call table.maxn()
> instead.  It takes just as long as table.has_holes() would, and it
> gives you the answer you're looking for as well.
> 
> Greg F
> 

Using "#t == table.maxn(t)" as a test for no-hole tables does not work
(and I did not expect it to work given the definitions of #t and
table.maxn(t), just want to make sure this wrong advise does not stay
undisputed in the archives):
Lua 5.1.4  Copyright (C) 1994-2008 Lua.org, PUC-Rio
> t={1,nil,3}
> =#t
3
> =table.maxn(t)
3

</nk>