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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: What about a Static_Assertion?
Date: Tue, 23 Jul 2013 20:57:05 +0200
Organization: Ada @ Home
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Date: 2013-07-23T20:57:05+02:00
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Le Tue, 23 Jul 2013 20:43:19 +0200, Dmitry A. Kazakov  =

<mailbox@dmitry-kazakov.de> a =C3=A9crit:

> On Tue, 23 Jul 2013 20:07:54 +0200, Yannick Duch=C3=AAne (Hibou57) wro=
te:
>
>> Don't you believe it would be great to have static assertion just lik=
e  =

>> we
>> have static predicates?
>
> What is the difference between assertion and precondition or invariant=
?
>

An assertion may applies to multiple things at a time. I like to see an =
 =

assertion as hypothesis (and I prefer the hypothesis to be statically  =

checkable :-P ), and it is an hypothesis I may refer to from multiple  =

place in a package (although I may like to duplicate it in multiple case=
),  =

not from a single sub=E2=80=91program.

Also, there is no distinction between private and public predicates, whi=
le  =

a can put an assertions in a package body, which I will refer to, to  =

=E2=80=9Cprove=E2=80=9D the implementation is correct (at least free of =
runtime errors), I  =

can't do the same with a predicate. For hypothesis used in the  =

implementation only, public sub=E2=80=91program predicates are not suita=
ble.

By the way, I don't believe assertions are seen as a deprecated feature,=
  =

and that suggest from many one's eyes, it is indeed different and can't =
be  =

replaced by the actual predicates.

-- =

=E2=80=9CSyntactic sugar causes cancer of the semi-colons.=E2=80=9D [1]
=E2=80=9CStructured Programming supports the law of the excluded muddle.=
=E2=80=9D [1]
[1]: Epigrams on Programming =E2=80=94 Alan J. =E2=80=94 P. Yale Univers=
ity