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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: Manifesto against Vector
Date: 07 May 2004 20:15:00 +0100
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Date: 2004-05-07T20:15:00+01:00
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Jeffrey Carter <spam@spam.com> writes:

> To my way of thinking, you depend on any types you may have objects
> of and anything you may invoke. A derived type is not the same type
> as its parent, nor are its operations the same as its parent's
> operations. Since type extension is a form of type derivation, I
> apply the same rules to type extension that I did to type derivation
> in Ada 83: the parent must be either a predefined type, or a type
> declared in the same declarative region as the child. Anything else
> quickly becomes unreadable.

A(n abstract) parent, and its operations, define a contract that
extensions must obey. I guess it's like recursion, at some point you
just have to take things on trust.

-- 
Simon Wright                               100% Ada, no bugs.