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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Style Question: normal record vs discriminated null-record.
Date: Tue, 3 Jun 2014 09:19:42 +0200
Organization: cbb software GmbH
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Date: 2014-06-03T09:19:42+02:00
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On Mon, 02 Jun 2014 20:44:24 -0600, Shark8 wrote:

> Ok, given some sort of alert-system (meaning there shouldn't be any/much 
> in the way of value manipulation of those objects) is it preferable to 
> use a discriminated null-record or a record with normal components?
> 
>      Type Grievousness is (Warning, Error);
>      Type Circumstance is (Expired_Data, Bad_Request, Malformed_Data);
> 
>      Type Alert_1(Severity : Grievousness; Condition :  Circumstance) is
>      null record;
> 
>      Type Alert_2 is record
>          Severity  : Grievousness;
>          Condition : Circumstance;
>      end record;

My rule of thumb - discriminants whenever possible, components as a
fallback.

I wished Ada allowed discriminants of any type.

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