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From: guest@alfrat.uucp (Mr. Guest User)
Newsgroups: comp.object,comp.lang.misc,comp.lang.eiffel
Subject: Re: A Hard Problem for Static Type Systems
Summary: Detour Denotational Semantics of Eiffel?
Message-ID: <311@alfrat.uucp>
Date: 3 May 91 10:17:07 GMT
References: <1991Apr20.010347.28984@leland.Stanford.EDU> <554@eiffel.UUCP> <1991May1.194620.1141@leland.Stanford.EDU> <566@eiffel.UUCP>
Reply-To: dave@alfrat.UUCP (Dave Cullen)
Organization: A+F System-Entwicklung, W-Germany
Lines: 28

This is actually a slight detour from the main thread of this
discussion but C'est la vie.

In article <566@eiffel.UUCP> bertrand@eiffel.UUCP (Bertrand Meyer) writes:

>covariant redefinition policy. If the mathematical models for
>contravariance are simpler, then that's too bad for mathematics.
>Denotational semantics 0, software engineering 1.
>(By the way I love denotational semantics, even wrote a book on it,
>but I believe that scientists should build theories to fit the practice,
>not the other way around.)
>

Does this mean that there exists no formal description of Eiffel
in terms of Denotational Semantics? If this is the case, what
method is used to define the semantics of Eiffel (including
the semantics of the type checking)? I have heard (correct me
if I'm wrong) that the syntax of Eiffel is now Public Domain
and assume that other vendors must be currently developing
their own compilers. How can we be sure that implementations
of Eiffel comply to Bertrand Meyers definition, I would hate
to see Eiffel take the same road as PASCAL.

For the record, I too am a fan of Denotational Semantics and
also of Software Engineering, I'd like to see the score as
Denotational Semantics 1, Software Engineering 1.

Dave Cullen                       ...!unido!alfrat.uucp!dave