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From: =?utf-8?Q?Yannick_Duch=C3=AAne_=28Hibou57?=
 =?utf-8?Q?=29?=
 <yannick_duchene@yahoo.fr>
Newsgroups: comp.lang.ada
Subject: Re: Lost in translation (with SPARK user rules)
Date: Thu, 27 May 2010 10:13:55 +0200
Organization: Ada At Home
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Date: 2010-05-27T10:13:55+02:00
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Le Wed, 26 May 2010 12:57:11 +0200, Yannick Duch=C3=AAne (Hibou57)  =

<yannick_duchene@yahoo.fr> a =C3=A9crit:
>> If that is the conclusion left in the SIV file then the user rule to
>> prove it is:
>>    user_bitwise(1): bit__and(X, 2) =3D 0 -> X div 2 mod 2 =3D 0
>> may_be_deduced .
> I remember about this, this was just that I did not suspected this had=
  =

> to be a so exact match.
Finally, there is a work-around: if the Simplifier expect an expression =
 =

which exactly match the one provided as a user rule, and there is not a =
 =

direct matching expression in the source, then just use Simplifier's  =

embedded rules to prove an expression is equivalent to the one the  =

Simplifier expect an exact match.

That is, if there a user rule of the form

    my_rule(1) Conclusion_1 may_be_deduced_from [Expression_1].

and the source unfortunately contains only

    Expression_2

then try something like

    --# check Expression_2 -> Intermediate_Expression(1);
    --# check ...;
    --# check ...;
    --# check Intermediate_Expression(N) -> Expression_1;

and here it is.

-- =

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.