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From: Robert A Duff <bobduff@shell01.TheWorld.com>
Newsgroups: comp.lang.ada
Subject: Re: How to detect OS type and version?
Date: 16 Oct 2005 11:59:57 -0400
Organization: The World Public Access UNIX, Brookline, MA
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Date: 2005-10-16T11:59:57-04:00
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Ray Blaak <rAYblaaK@STRIPCAPStelus.net> writes:

> What I would do in your case is to make my own project-specific enumerated
> type and decide the appropriate current literal value at startup based on the
> the string-based values returned from querying the OS.

In my case, we have an enumeration type, and we compile in the value.
(That is, we have a package spec with three versions, and the build
scripts pick the right one.)  There's no need to query anything at run
time (in my project).

> I guess what I care about is that the built in OS query that would live
> somewhere under the System or Ada hierarchy would not return an enumerated
> type, but rather a string.
> 
> That is, the enumeration should not be built into the language, since
> it is not at all a stable enough set of values for the long
> term. Imagine being able to code to an updated set only every 10
> years, which seems to be Ada's upgrade cycle.

I agree that an enum type would not work here, as a language feature.
But neither would a string or anything else -- there is no solution
at the language level.  This issue has to be solved by each project,
I think.

- Bob