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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Exceptions in (dynamic) predicates
Date: Thu, 31 Oct 2013 21:52:36 +0000
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Date: 2013-10-31T21:52:36+00:00
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A StackOverflow answer contains the following code:

   subtype XYZ is ABC
     with Dynamic_Predicate =>
     ((XYZ.A in Positive) and
        (XYZ.B not in Positive)) or else raise Constraint_Error;

(actually, the original didn't have the 'else', with unhelpful results :)

I can't see where in the ARM "raise Constraint_Error" can be a
(component of a) boolean expression? or is this a GNATism?