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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: Strategies with SPARK which does not support exceptions
Date: Thu, 17 Jun 2010 17:33:29 +0200
Organization: Ada At Home
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Date: 2010-06-17T17:33:29+02:00
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Hello,

(This topic will probably not be the most exiting topic to some people).=


When I use SPARK, or even when I don't use SPARK while I still have SPAR=
K  =

design style in mind (even with Pascal which I still use), I have like a=
ny  =

one else, to forget about exceptions.

The only one thing which seems simple and clean enough I could figure, i=
s  =

to use a Boolean variable, named =E2=80=9COK=E2=80=9D, and a sequence of=
 =E2=80=9Cif OK then=E2=80=9D  =

statements. That is, execution of one sequence of statements, which set =
OK  =

to False is something goes wrong, and execute clean-up statements by the=
  =

way. Then a next sequence of statements wrapped in a =E2=80=9Cif OK then=
=E2=80=9D which do  =

the same, and so on with next statements groups which are also wrapped i=
n  =

a =E2=80=9Cif OK then=E2=80=9D (as many as needed).

Although this seems clean and maintainable enough to me so far, I was  =

still wondering how other people deal with this (and may be by the way, =
I  =

may have comment about why my way could be bad in some way).

Note: a similar strategy may also obviously applies to fulfill the =E2=80=
=9Conly  =

one single exit point=E2=80=9D requirement.

So, let us talk and comment about design strategies in this area (if  =

someones wish to).