Re: grassroots thoughts on access types

[Mehdi Saada <00120260a@gmail.com>]

>It is semantically a pointer, an object that directly references another
object.

Well, you have a point, but aren't you a bit nitpicking ?
I think one can write:

type CONTAINER_TYPE is private
      with Iterable =>  (First        => First,
                         Next         => Next
                         Has_Element  => Has_Element,
                         Element      => Get);
type CURSOR is limited private;
type ELEMENT is new WHO_CARES;
function GET(LIST: COINTAINER_TYPE, CURSOR_OBJECT: CURSOR) return ELEMENT,
function FIRST(LIST: CONTAINER_TYPE) return CURSOR;
function NEXT(LIST: CONTAINER_TYPE, CURSOR_OBJECT: CURSOR) return CURSOR;
function HAS_ELEMENT(LIST: CONTAINER_TYPE, CURSOR_OBJECT: CURSOR) return BOOLEAN;

private

type CURSOR is POSITIVE;
type CONTAINER_TYPE is ...

there isn't much difference in my understanding between this numeric CURSOR and a regular array index type. None of the usual problem of dynamic allocation, dangling pointers, unchecked this-or-that here.
So I don't really see why it should be forbidden in secure, deterministic Ada subset.