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From: "Jeffrey R. Carter" <spam.jrcarter.not@spam.not.acm.org>
Newsgroups: comp.lang.ada
Subject: Re: Type invariants and private extensions?
Date: Tue, 12 Sep 2017 21:56:39 +0200
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Date: 2017-09-12T21:56:39+02:00
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On 09/12/2017 08:54 PM, Victor Porton wrote:
> 
> A SPARQL query may return boolean, graph, bindings, etc. The return type is
> determined by the text of the query.
> 
> I want to make derived types of a query which are validated that their
> return is of a certain type (e.g. a boolean). This certainly useful in a
> language like Ada intended for reliability and maximum runtime check during
> debugging.

"I want to" is not the same as "there is no way to solve the problem in current 
Ada". Ada has a feature that provides exactly what you need. It's called a 
variant record.

-- 
Jeff Carter
"Why don't you bore a hole in yourself and let the sap run out?"
Horse Feathers
49