Re: Safety-critical development in Ada and Eiffel

[jsa@alexandria.organon.com (Jon S Anthony)]

In article <EDnA6M.FGx@syd.csa.com.au> donh@syd.csa.com.au (Don Harrison) writes:

> in one place all the modules used by another. In contrast, because
> Eiffel *does* support safe reuse of components, it isn't as
> important to separately document the modules used.

???  I don't think so.


> :If you let code anywwhere
> :reach anywhere easily, you have a recipe for mess.
> 
> I agree for Ada. I don't agree for Eiffel which gives you a high
> level of confidence that you can reuse with impunity. Reusing
> certain modules may happen to be nonsensical but that's a design
> issue - not a reuse issue - and irrelevant to this argument.

Come on Don, this problem is in Eiffel as well - it just doesn't offer
any support to fix it.  You have to punt out to something like LACE
which is just a hack.  A hack that works, but a hack nonetheless.

> :The requirement to write a with clause is also the requirement to think
> :about whether it is appropriate for the unit you are in to "with" the
> :unit that you think you need.
> 
> I disagree. An Eiffel software engineer thinks about this when they
> *use* a module.

Irrelevant.  The point is you can't just have "classes" - they do not
support large scale structures.  That's a bit part of why there even
is a LACE for crying out loud.


[[Aside: You know, Eiffel is a fairly decent language - not great, but
decent.  I'm with Brian Rogoff on this - all programming languages
suck.  And Eiffel sucks less than some but definitely more than
others.  IMO, it clearly sucks more than Ada, but people can disagree
on this as they both suck.  The big problem here is simply that many
Eiffel folk act as if it's a religion and sound very similar to the
sort of Ada fanatic that you used to run into.]]

/Jon
-- 
Jon Anthony
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617.484.3383
"Nightmares - Ha!  The way my life's been going lately,
 Who'd notice?"  -- Londo Mollari