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From: Georg Bauhaus <bauhaus@futureapps.invalid>
Newsgroups: comp.lang.ada
Subject: Re: type conversion
Date: Mon, 13 Oct 2014 01:05:53 +0200
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Date: 2014-10-13T01:05:53+02:00
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On 12.10.14 11:37, Pascal Obry wrote:
> To control the message or the exception to be raised one can use the
> Predicate_Failure aspect:
>
> subtype Integer_String is new String
>     with Dynamic_Predicate => Integer'Value (Integer_String) in Integer,
>          Predicate_Failure => "not an integer string";

Is Predicate_Failure a new aspect in GNAT? My RM does not list it,
and GNAT GPL 2014 rejects it. GNAT does, however, accept

    subtype Integer_String is String
      with Dynamic_Predicate => Integer'Value (Integer_String) in Integer
            or else raise Assertion_Error with "not an integer string";

(And warns that one should use 'Valid instead of a membership test,
even though there is no object to which one could apply 'Valid.)