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From: Pascal MALAISE <malaise@magic.fr>
Subject: Re: PRECOMPILATION
Date: 1999/02/10
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Tom Moran wrote:
> 
> >Are there precompilation instructions in Ada95,
> >like in C (#ifdef,...etc) ? In other words, how can
> >I set compilation conditions ?
>   Most compilers are smart enough to delete code in a situation like:
>   Sometimes : constant Boolean := False;
> ....
>   if Sometimes then
>     stuff;
>   end if;
> ie, if the optimizer knows "stuff" can never be executed, it will
> simply drop it and the if-test.
>    Having worked on well known shrinkwrap software coded with the C
> preprocessor, I would STRONGLY recommend against going that route.
> Yes, it's just a tool, and judiciously used can be useful.  So's a
> hydrogen bomb.

Is it legal Ada to write
Sometimes : constant Boolean := False;
if Sometimes then
  -- representation clause
else
  -- another representation caluse of the same type
end if;

I think the error will be detected far before the optimizer is involved.

-- 
Pascal MALAISE
(priv) mailto:malaise@magic.fr
(prof) mailto:malaise@fr.airsysatm.thomson-csf.com