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From: "Jeffrey R. Carter" <spam.jrcarter.not@spam.not.acm.org>
Newsgroups: comp.lang.ada
Subject: Re: syntaxic exploration
Date: Sat, 23 Dec 2017 17:23:29 +0100
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Xref: reader02.eternal-september.org comp.lang.ada:49611
Date: 2017-12-23T17:23:29+01:00
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On 12/22/2017 11:11 PM, Niklas Holsti wrote:
> 
> I think the aggregate form (null array) was suggested some time ago, in analogy 
> with the existing (null record). It looks good to me, but as I remember, there 
> was some objection. One problem is that if the index type has exactly one value, 
> then a null array with that index type cannot exist (because then A'First = 
> A'Last for any such array A).

Actually, a null array of such a type can exist if it's a string type, because 
you can use the string literal "" for such types. AIUI, 'Last is undefined for 
such a value. Allowing (null array) for non-string array types with an index 
type with a single value would presumably work the same.

-- 
Jeff Carter
"The time has come to act, and act fast. I'm leaving."
Blazing Saddles
36