Re: Object-Oriented style question

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

On Jan 8, 1:45 pm, Georg Bauhaus <rm-host.bauh...@maps.futureapps.de>
wrote:

>     function Info (Item : in T) return Value;
>     function Info_1 (Item_Doubly_Indirect : access T) return Value;
>     function Info_2 (Item_Doubly_Indirect : access constant T) return Value;
>     function Info_3 (Item_Doubly_Indirect : not null access constant T) return Value;

> I am thinking that the operations
> Info and Info_3 are almost the same,

Almost. And considering the fact that T is tagged and is passed by
reference, you might argue that their meaning is the same.

But I think that in one particular case you might want to distinguish
between these profiles - access value is a "name" of the object, not
the object itself, and therefore can be used for more involved lookup.
Like in a dictionary, where access values are lightweight keys.
Then, the real meaning of Info_3 would be "tell me what you know about
the object whose name is this-or-that", using perhaps multiple
dictionaries (or should I say "caches"?) or complicating this idea in
any other way you like.

In short: access value is a "name" of the object and therefore Info
and Info_3 do not have to mean the same.

I agree, however, that in most cases your original Info is the most
obvious and easy to decipher. At the didactic level this is what
should be used for teaching OO.

--
Maciej Sobczak * http://www.inspirel.com