Re: Lua 5.2 Length Operator and tables (bug?)

[Dirk Laurie <dirk.laurie@...>]

>>
>>   t      = { 1, 2 }
>>   t[ 2 ] = nil
>>   t[ 3 ] = 3
>>
>>   print( t[ 1 ], t[ 2 ], t[ 3 ], issequence( t ) )

>
> That's not a counterexample, that's just a special case. In this case,
> this test is reporting that t IS a sequence, and #t is returning the
> length of it -- what it isn't reporting is that there are also
> non-sequence parts of t. If you want THAT test, of course, you can
> code for it too.
>

>From the 5.2 manual:

   We use the term sequence to denote a table where the set of all
positive numeric keys   is equal to {1..n} for some integer n, which
is called the length of the sequence

In this case, the set of all positive numeric keys is {1,3} — you can
verify that by iterating through pairs() — which does not satisfy the
definition.