Re: C API - lua_next traversal of "array" table

[Peter Aronoff <telemachus@...>]

Andrew Starks <andrew@starksfam.org> wrote:
> ...then you can live with the definition of a sequence being:
> 
> "Any table containing a non-nil value at index 1. The length of the
> sequence is the number of non-nil keys from `1..n`."
> 
> Simple. Easy to test. If you need more, Lua has ways to provide it.

I’m afraid you haven’t really answered my question. You’re proposing (or
using, at least) a definition of ‘sequence’ different from the one in Lua’s
manual. The manual explicitly says this:

> We use the term sequence to denote a table where the set of all positive
> numeric keys is equal to {1..n} for some non-negative integer n, which is
> called the length of the sequence (see §3.4.7).

And §3.4.7 adds:

> Note that a table like
>
>	{10, 20, nil, 40}
>
> is not a sequence, because it has the key 4 but does not have the key 3.
> (So, there is no n such that the set {1..n} is equal to the set of
> positive numeric keys of that table.)

My question to you was: *why* change the manual’s definition? That
definition is also simple and easy to test. And, frankly, it’s a lot more
intuitive to me than yours. (As far as any of this is intuitive, at
least...)

P
-- 
We have not been faced with the need to satisfy someone else's
requirements, and for this freedom we are grateful.
    Dennis Ritchie and Ken Thompson, The UNIX Time-Sharing System