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From: "Jeffrey R. Carter" <spam.jrcarter.not@spam.not.acm.org>
Newsgroups: comp.lang.ada
Subject: Re: class wide iterable (and indexable)
Date: Tue, 22 Jan 2019 18:04:41 +0100
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Xref: reader01.eternal-september.org comp.lang.ada:55325
Date: 2019-01-22T18:04:41+01:00
List-Id: <comp.lang.ada>

On 1/22/19 12:15 AM, Randy Brukardt wrote:
> 
> Moreover, in a new Ada-like language, it would make the most sense to
> completely unify containers and arrays, which would mean that arrays would
> be more like Vectors than like Ada arrays. For instance, in a Vector, the
> lower bound is fixed for all values of a particular type. That would
> eliminate a lot of programming errors that happen in Ada programs (many
> programs fail to deal with unusual lower bounds, because it's hard to get
> right).

Ada has always had the ability to define array-like types with a fixed lower bound:

type String_From_1 (Length : Natural) is record
    Value : String (1 .. Length);
end record;

I use such constructs when appropriate (in mathematics, for example, matrices 
and vectors have indices with lower values of 1, and a decent implementation 
should reflect and enforce that). One might argue that the reason they're not 
used more often is because of the value of having array types with variable 
lower bounds, but I doubt it.

-- 
Jeff Carter
"He didn't get that nose from playing ping-pong."
Never Give a Sucker an Even Break
110