Re: Returning ranges from a function (was: How to loop (elegant) throug a vector ?)

[Maciej Sobczak <see.my.homepage@gmail.com>]

On 22 Cze, 20:47, Stefan Bellon <bel...@software-erosion.org> wrote:

> You need to store the two words for First and Last (or First and
> Length). And indeed, this is what GNAT does. The 'Size of the array
> object returned is two words in size.

Now I have noticed the for Empty_Component'Size use 0 part. Sorry for
the confusion, but see below for more. :-)

> The question is
> whether this optimisation (for 'Size use 0) can always be guaranteed.

I have a better question: is it *legal*?

Consider 3.6/13:

"A one-dimensional array has a distinct component for each possible
index value."

What does it mean - "distinct"? Doesn't it exclude overlays?

What about "independent addressability" from 13.3? The text is a bit
dense, but I conclude that the 'Size attribute does not have to be
strictly obeyed by the implementation.

--
Maciej Sobczak * www.msobczak.com * www.inspirel.com