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From: Dennison <dennison@iag.net>
Subject: Re: Two ideas for the next Ada standard
Date: 1996/09/07
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Date: 1996-09-07T00:00:00+00:00
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Robert Dewar wrote:
> 
> That's very confused. Putting the text of the private part in the same
> file as the body creates a source dependence it is true, meaning that if
> you modify a body, you have to recompile clients, but it does not mean
> that a client has to compile the body (that is only needed in the presence
> of inlining or generics), so the presence of with's in the body is quite
> irrelevant.

You're right. I am confused. Let's try an example. Supose unit A withs spec
B. Spec B withs units C and D, and body B withs units E-K (7 extra units).

Now with private parts in the spec, the only time A has to be recompiled is
when A, the spec of B, C or D changes. But if B has a private part in the 
BODY, it seems to me that A would have to be recompiled whenever A, the spec
of B, the body of B, or C, D, E, F, H, I, J, or K change. Thus this change
(assuming even distribution) makes A nearly 3 times more likely to be 
obsoleted by a source change. If we start adding with's to units C-K, the
odds get even worse.

So what am I missing here?


> As for compilations taking DAYS (with a shout), this is like political
> campaign rhetoric, it results in FUD but is short on technical facts :-)

Obviously this could only happen if a recompile of the entire system took
that long. Admittedly, the most extreme I have ever seen was 1 day. But
if they hadn't used a dedicated VAX with 2 processors, it could easily have
taken twice as long.

-- 
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