Re: GCC 4.0 Ada.Containers Cursor danger.

["Randy Brukardt" <randy@rrsoftware.com>]

"MMM" <terekhov@emc.com> wrote in message
news:1121194262.036046.38230@g49g2000cwa.googlegroups.com...
> I agree with you completely. The problem is that Matthew insist that
> there is no need for plain
> vanilla unordered set and/or plain vanilla unordered hash, they do not
> even exist in computer science
> and the basis of the Ada.Containers library should form Ordered_Set and
> Ordered_Hash.

You seem to be confused about the purpose of the Ada.Containers library. It
is provide the most useful containers in the standard fashion. It's not to
be complete in any way. The names and design of containers was specifically
selected to make it easy to add other containers in the future, like
unordered sets and maps, bounded forms, protected forms, and the like.

One of the first things that we did was to discard pure unordered sets and
maps to reduce the size of the library. (It's now about the maximum size
that we could define.) The reason has that for virtually all needs, an
ordered set or map will suffice. The performance characteristics are
similar, the overhead is not significant in most applications, the
operations are a superset, so they are good enough. The reverse is clearly
not true (if you need ordering, it can't reasonably be simulated with an
unordered set or map).

Clearly, the library could have lots of other kinds of containers, but these
are going to be used much less often than the ones defined. We hope that a
secondary standard is created down the road for such containers;
Ada.Containers just provides a foundation and vision for future work. And I
hope that it focuses future work so that we have more similar components
rather than a plethora of different designs. It's not going to be the
perfect design for everyone (probably, in fact, no one will think it to be
perfect), but as a standard, it will always be available to Ada users.

                           Randy.