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From: Ted Velkoff <velkoff@erols.com>
Subject: Re: Design by Contract
Date: 1997/08/27
Message-ID: <3403B678.6CB6@erols.com>#1/1
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References: <33E9ADE9.4709@flash.net> <EEsF5y.F5H@syd.csa.com.au>
 <34023BC4.2781E494@eiffel.com> <3402d123.0@news.uni-ulm.de>
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Organization: Erol's Internet Services
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Newsgroups: comp.object,comp.software-eng,comp.lang.ada,comp.lang.eiffel
Date: 1997-08-27T00:00:00+00:00
List-Id: <comp.lang.ada>


Robert Dewar wrote:
> 
> Nick said
> 
> <<But if you are allowed to change the merged specification/implementation
> and check
> that you haven't caused problems else where you are ok. It is true that
> with C++
> you have problems and have to be careful. Eiffel you don't, because
> there is just one file. Modula II as you point out you don't. Give the
> choice of the two different approaches, and having used both I would now
> always go for spec and impl. in one file.
> >>
> 
> That's truly surprising. One of the things that virtually everone who
> uses Ada agrees on is that the separation of spec and body is an invaluable aid
> to system structuring. Of course there is no concern about incomaptibilities
> in Ada, since everything is always checked for consistency -- I
> see that in C++ this would be a prblem, but
> going to a single file is a horrible way to solve the problem.

Having used each of the languages cited, I vote for Eiffel's one file 
with extracted specification.  When needing to change an interface, I've 
found it annoying to have to make the same change in two different 
places.  Of course, Ada's compilable package specs are infinitely better 
than C++ header files.

-- Ted Velkoff