Re: BUG in table.concat

[Alex Sandro Queiroz e Silva <asandroq@...>]

Hallo,

Leo Razoumov wrote:
> NOTE: the definition above never explicitly addresses the issue of
> arrays with holes.
> Is a hole an element with nil as a value (nil is nither string nor number)??
> See below.

     If it has holes it is *not* an array. This is the tricky part.

> NOTE: the manual explicitly says that nil cannot be a value in an
> array or table (nil also cannot be a valid key).
> Direct interpretation of the paragraph above: "t[2]=nil means that
> array t does not contain an element t[2]"
> It is different from "t[2] exists and has a value of nil".

     Correct.

> (3) another discussion of arrays with holes
> http://www.lua.org/manual/5.1/manual.html#2.5.5
>
> "For a regular array, with non-nil values from 1 to a given n, its
> length is exactly that n,
> the index of its last value. If the array has "holes" (that is, nil
> values between other non-nil values),
> then #t may be any of the indices that directly precedes a nil value
> (that is, it may consider any such nil value as the end of the array)."
>
> NOTE: according to (3) arrays can have elements with nil as a value,
> contradiction with (2) "the value of a table field can be of any type
> (except nil)."

     Wrong. You should read "nil values" here as "absence of values".

-alex
http://www.ventonegro.org/