Re: Papers on the Ariane-5 crash and Design by Contract

[jsa@alexandria (Jon S Anthony)]

In article <33330FE5.3F54BC7E@eiffel.com> Bertrand Meyer <bertrand@eiffel.com> writes:

> > From this we learn that Java and Ada 95 are not properly designed for
> > Design by Contract.
> 
> Which is the simple truth. The designers of these languages have
> explicitly rejected the inclusion of assertions. Why? They are the
> ones to ask.  I am sure they must have their reasons (however
> unlikely it is I would find these to be good reasons).

It is simply amazing to see you sit there (or type there) and say in
one breath "Which is the simple truth" and then proceed to make an
absolutely false statement in the next.  In fact, it is extremely
disappointing and makes you look ridiculous.

Ada _has_ assertions.  Their form is not of the same syntactical look
as Eiffel's.  So what?  They take the form of constraints, in
particular (wrt to the case at hand) subtype constraints.  They are
_not_ as flexible or full "featured" as Eiffel's but they are
certainly there and in the Ariane case, they are every bit as capable
as Eiffel's.  There is no difference in this sort of case.  You are
just plain a) wrong or b) - well it doesn't take a genius to fill in
the obvious answer to this option.


> > It's bad enough that you post statements that are explicitly
> > contradicted by the Ariane V final report (e.g. that the IRS could not be
> > tested in a black-box environment). When you post statements that are
> > contradicted by your *own* paper...
> 
> No evidence has been furnished of either of the purported
> contradictions.  

Do you have any idea how ridiculous this sort of statement makes you
look???  You are not doing Eiffel any favors here...

/Jon

-- 
Jon Anthony
Organon Motives, Inc.
Belmont, MA 02178
617.484.3383
jsa@organon.com