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From: Dmitry A. Kazakov <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Is the Writing on the Wall for Ada?
Date: Tue, 30 Sep 2003 15:56:21 +0200
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Date: 2003-09-30T15:56:21+02:00
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On Tue, 30 Sep 2003 12:21:00 GMT, Marin David Condic
<nobody@noplace.com> wrote:

>It would be nice to have unbounded string versions of all the 
>subprograms that use strings. Open, Create, etc., all could be 
>duplicated with an Unbounded_String parameter. Don't forget the 
>sub-packages like Integer_IO, et alia. They have string parameters as 
>well and I'd like to be able to use Unbounded_String everywhere.

Which means that Unbounded_String has to be a subtype of String. 

Actually interface inheritance should have solved this (by providing
user-defined type conversions). You inherit a String interface and
implement it via Unbounded_String, and here you are, all instances are
substitutable where a String is expected.

Unfortunately, the AI goes other way.

---
Regards,
Dmitry Kazakov
www.dmitry-kazakov.de