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Date: Wed, 4 Apr 2018 17:44:21 -0700 (PDT)
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Subject: Re: Interesting article on ARG work
From: Mehdi Saada <00120260a@gmail.com>
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Xref: reader02.eternal-september.org comp.lang.ada:51336
Date: 2018-04-04T17:44:21-07:00
List-Id: <comp.lang.ada>

> Is that different from contracts?
It's an expansion of contracts. AFAIK, One can define in SPARK whole compil=
ation units, whose only purpose is to help writing contracts, for arbitrari=
ly complex dynamic or static checking.
The principle is, with a specific assertion policy, anything marked with th=
e GHOST aspect would disappear from the code (and object code), but the pro=
gram would be functionally identical.

.. One thing I found (a bit) irritating from a beginner point of view, is t=
hat normal visibility rules still still holds in contracts/assertions. It w=
ould be much easier to write contracts about conditions of (at least) thing=
s declared in the private part. It would be nonsensical to let them reach t=
he body though, that I can understand. But why not packages' private part ?