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From: Brian Drummond <brian@shapes.demon.co.uk>
Newsgroups: comp.lang.ada
Subject: Re: Efficient Sequential Access to Arrays
Date: Thu, 26 Jul 2012 10:10:39 +0000 (UTC)
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Date: 2012-07-26T10:10:39+00:00
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On Thu, 26 Jul 2012 01:38:41 -0700, Keean Schupke wrote:

> This is an equivalent concept to nullable, so two questions:
> 
> What is the literal for 'invalid', IE:
> 
> X : Index := #INVALID -- we should be able to initialise to invalid.
> 
> if X = #INVALID -- I want to be able to test for invalid.

There's an attribute for that.

if X'Valid ...

- Brian