Re: Private constant of tagged limited controlled type

[Jeffrey Carter <spam.jrcarter.not@spam.not.acm.org>]

On 10/21/2011 11:14 PM, Malaise wrote:
> The following complains that "initialization of limited object
> requires aggregate or function call":

Right.

> with Ada.Finalization;
> package Pack is
>    type T is tagged limited private;
>    C : constant T;
> private
>    type T is new Ada.Finalization.Limited_Controlled with record
>      I : Integer := 0;
>    end record;
>    V : T;
>    C : constant T := V;
> end Pack;
> Aggregate seems impossible because Limited_Controlled is abstract and
> anyway T is very complex in fact.

I suggest you read ARM 4.3.1 and 4.3.2. You can write an aggregate of the form

(Ada.Finalization.Limited_Controlled with others => <>)

> A function (returning tagged type) has to be visible and anyway cannot
> return V (in Ada 2005).

This is an unusual claim. The extended return statement was introduced 
specifically for returning limited types from a function. You ought to read ARM 
6.5. You could write

return X : T;

to return a value of T with all components set to their default values.

-- 
Jeff Carter
"We use a large, vibrating egg."
Annie Hall
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