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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Generic Zero Length Array
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Date: Sat, 23 Feb 2008 17:16:18 +0100
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Date: 2008-02-23T17:16:20+01:00
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On Sat, 23 Feb 2008 09:27:26 -0500, Robert A Duff wrote:

> I suppose ranges could be characterized by 'First/'Length,
> instead of 'First/'Last.  And eliminate 'Last from the language.

Is Index'First any better than Index'Last? Null range does not have any
indices in it. That includes Index'First. Otherwise each element of Index
would have an individual null range associated with it.

(I think there should be something like null of Universal_Range.)

> Or else say 'Last raises Constraint_Error if 'First = 'Base'First
> and 'Length = 0.

A'Range /= A'First..A'Last?

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de