Re: Ada.Locales pseudo-string types

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Wed, 08 Aug 2012 17:01:23 +0300, Niklas Holsti wrote:

> On 12-08-08 14:59 , Dmitry A. Kazakov wrote:

>> BTW, if you go that far you should also allow conversions between any array
>> types of convertible elements. E.g. between arrays of floats and arrays of
>> integers etc.
> 
> Well, for explicit value conversions, why not? But I don't think that
> there is significant need for such conversions on the array level.

I needed to convert array of access types in some cases. But I agree that
there is no significant need in array conversion, in any array conversion,
I would add. Don't we consider conversions bad, in Ada? If so, we should
rather eliminate cases where conversions are needed, rather than inventing
more and more sophisticated ways of conversion.

> What I have sometimes found annoying is that operations on arrays of a
> parent type cannot easily be applied to arrays of a derived type.
> For example:
> 
>    type Parent is (A, B, C);
>    type Parent_Arr is array (Positive range <>) of Parent;
> 
>    procedure Print (Item : in Parent_Arr)
>    ...
>    end Print;
> 
>    type Child is new Parent;
>    type Child_Arr is array (Positive range <>) of Child;

If arrays had classes you could inherit the Parent's interface which would
bring Print with it.

> The operation Print on Parent_Arr is not inherited by Child_Arr,

Why should it? Child_Arr is unrelated to Parent. Somewhere in its
declaration Child_Arr must say "new Parent" or "and Parent." Such type
relationships must be manifested, not implied.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de