Re: Specialization

["Sergey Koshcheyev" <serko84@hotmail.com>]

"Jim Rogers" <jimmaureenrogers@worldnet.att.net> wrote in message
news:3CF6CF7D.8000704@worldnet.att.net...
> Baugereau wrote:
> > Ok so this is the difference of philosophy with STL's vector, which is
plain
> > value-oriented.
> > What I dislike here is the lack of locality of the elements, and the
need to
> > "new" every time I add an element...
> > Any comment?
>
> The difference is that in C++ you "new" the element before you add
> it to the vector (in the constructor).

This is wrong, if you have a vector<BigObject> in C++ STL, then what is
stored are BigObjects, not pointers to them. There are a few tricks that can
be used to achieve this ("placement new", and also the fact that it is
possible to call object destructors manually).

> If you were to dynamically allocate all your objects in Ada, just as
> you do in C++, then the container would not need to perform any of the
> dynamic allocation. You could simply add references to the objects
> just like you do in C++.

When using STL containers, you can add a local object into the container,
for example, and it will be properly copied.

> You will also find that Ada scoping rules are much more strict than C++
> scoping rules. This can influence the way you design your container
> package.

The scoping rules are not the problem, I think. You can copy the objects, if
needed. To imitate C++ in this respect, you just need some way (possibly, a
hack) to manually Initialize and Finalize the inserted objects, and ensure
that the compiler doesn't also try to do that. Maybe playing with
Storage_Pools a little will lead to a solution. Or maybe there is a more
Ada-like way, I don't know.

Sergey.