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From: Niklas Holsti <niklas.holsti@tidorum.invalid>
Newsgroups: comp.lang.ada
Subject: Re: syntaxic exploration
Date: Mon, 25 Dec 2017 20:27:25 +0200
Organization: Tidorum Ltd
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Xref: reader02.eternal-september.org comp.lang.ada:49639
Date: 2017-12-25T20:27:25+02:00
List-Id: <comp.lang.ada>

On 17-12-25 16:42 , Mehdi Saada wrote:
> More importantly, why would anyone use an enumeration
> type with only one  value ? I don't get it.

It's a limit case that comes up fairly often when one creates generic 
software components parametrized by enumeration types, or other discrete 
types. (Sometimes one would like to use such a component with an 
enumeration type that has _no_ elements, but that seldom works...)

Null record types (with no components) and empty arrays are similar 
limit cases. The number zero and the empty set are others. It is 
important that language has sensible and consistent rules for these 
limits (for example, a loop over an empty array should execute the loop 
body zero times) so that generic code can be written without always 
handling these limit cases separately.

-- 
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
       .      @       .