Re: table.maxn...
[
Date Prev][
Date Next][
Thread Prev][
Thread Next]
[
Date Index]
[
Thread Index]
- Subject: Re: table.maxn...
- From: Roberto Ierusalimschy <roberto@...>
- Date: Mon, 1 Jun 2015 13:01:49 -0300
> The right question is not whether a table is a sequence, but whether
> the default #tbl is deterministic for the particular table, i.e. whether the
> table has no holes. Being a sequence is merely a sufficient condition. The
> iterations `for i=1,#tbl` and `for i in ipairs(tbl)` both ignore
> non-integer keys.
Sorry, but if you want to know whether '#tbl' has a reasonable meaning
(and is deterministic), then the right question is whether a table is
a sequence, because that is what the manual says:
Unless a __len metamethod is given, the length of a table t is only
defined if the table is a sequence, that is, the set of its positive
numerical keys is equal to {1..n} for some non-negative integer n. In
that case, n is its length.
The fact that the current internal implementation of '#' ignores
non-integer keys is an implementation detail.
-- Roberto