Re: limited agregate and limited components default initialization

[Jere <jhb.chat@gmail.com>]

On Saturday, March 31, 2018 at 10:07:20 PM UTC-4, Jean-Claude Rostaing wrote:
>    type ITEM_ACCESS;
>    type Item_Record is limited
>       record
>          Item: aliased Item_type;
>          Next : Item_Access;
>          Pred : Item_Access;
>       end record;
>    package Record_Pointers is new Pointers (Item_type => Item_Record);
>    type Item_Access is new Record_Pointers.Smart_Pointers;

Side note:  I couldn't get this to compile because Next and Pred
are incomplete types (so they too cannot be used a variable types.

The proper way to do it would be:
       type Item_Record;
       package Record_Pointers is new Pointers (Item_type => Item_Record);
       type Item_Access is new Record_Pointers.Smart_Pointers; 
    
       type Item_Record is limited
          record
             Item : aliased Item_type;
             Next : Item_Access;
             Pred : Item_Access;
          end record;

but your Pointers package will need an incomplete formal type for it to
work:

    generic
        type Item_Type(<>);
    package Pointers is
        -- stuff
    end Pointers;

and that might cause you other problems, but if you want to use
your smart pointers in a self referential type, you'll need your
smart pointer generic to use incomplete types.