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From: =?iso-8859-15?Q?Yannick_Duch=EAne_=28Hibou57=29?=
 <yannick_duchene@yahoo.fr>
Newsgroups: comp.lang.ada
Subject: Re: Spark and the Ada numerics annex
Date: Tue, 10 Aug 2010 13:40:18 +0200
Organization: Ada At Home
Message-ID: <op.vg7z1gcmxmjfy8@garhos>
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Date: 2010-08-10T13:40:18+02:00
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Le Tue, 10 Aug 2010 12:53:01 +0200, Ada novice <ycalleecharan@gmx.com> a=
  =

=E9crit:
>> You can create a "shadow" specification of the various Numerics
>> packages to get at their facilities.  See section 13.1 of the book
>> on Shadows.
>>  - Rod, SPARK Team
>
> Thanks for this information. I don't have the book yet and I have been=

> looking only at the first chapter which is freely available. I'll
> study this section when I get the book.
You can already get an idea right know (although the Barnes is still a  =

must have recommended reading), if you have a look at this AdaGem :
http://www.adacore.com/2010/02/25/gem-80/

Basically, this is re-interfacing things so that SPARK does not get angr=
y  =

with what it sees.

By the way, this is a natural strategy, ... sure you would have though  =

about it yourself. I've discovered this is named "shadow specification" =
 =

just at the moment, reading Rod. I did not knew before this had this nam=
e.


-- =

There is even better than a pragma Assert: a SPARK --# check.
--# check C and WhoKnowWhat and YouKnowWho;
--# assert Ada;
--  i.e. forget about previous premises which leads to conclusion
--  and start with new conclusion as premise.