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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Ada.Locales pseudo-string types
Date: Tue, 7 Aug 2012 09:20:27 +0200
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Date: 2012-08-07T09:20:27+02:00
List-Id: <comp.lang.ada>

On Mon, 6 Aug 2012 16:07:02 -0700 (PDT), Adam Beneschan wrote:

> I just sent a note to Ada-Comment requesting that To_String and
> From_String operations be added to Ada.Locales.  Maybe that isn't the
> right solution, but it does seem like something needs to change.

Yes, the right one would be an array subtype which is presently impossible
to have. E.g.

   subtype Language_Code is String (1 .. 3) of Character range 'a' .. 'z';

A similar case where array elements need to be constrained is an array of
class-wide elements as a replacement to generics:

   type Container is array (Positive range <>) of T'Class;
       -- No objects allowed
   type S is new T with ...;
   subtype Container_Of_S is Container of S;

Syntax is imaginary. Maybe, aspects could help better express element
constraints.

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