Re: smart pointer dangerous (no -> operator)

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

On 16 Sty, 21:08, Tero Koskinen <tero.koski...@iki.fi> wrote:

> If you want to manipulate the original object behind the smart pointer
> without using access types, you can use generics (or access to procedure):
>
> generic
>    type Element (<>) is limited private;
>    type Element_Access is access Element;
> package Smart_Pointer is
>    type Pointer is new Ada.Finalization.Controlled with private;
>    function Create (Object : Element_Access) return Pointer;
>
>    generic
>       with procedure Action (Object : in out Element) is <>;
>    procedure Update (Pointer_Object : Pointer);

I was thinking rather about something similar in spirit to
Update_Element/Query_Element in Ada.Containers.Vector.
One generic less -> easier to use.

Actually, it all comes with analogy. There is no indexing operator in
Vector (I mean - nothing like operator[] in C++, which returns a
reference to contained element), which is exactly the same kind of
problem as the lack of dereference in smart pointers.
If the problems are similar, why not go for similar solutions?

This, however, brings important question: what about performance? Is
it common for the compilers to inline such constructs (calls with
callbacks to local subprograms)?

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

Database Access Library for Ada: www.inspirel.com/soci-ada