From: "Joern W. Janneck" <janneck@...>
Date: 2000-06-20T22:24:59+02:00
Subject: [ruby-talk:03568] Re: Static Typing( Was: Waffling between Python and Ruby)


"Patrick Schoenbach" <Patrick.Schoenbach@eiffel.com> wrote in message
news:slrn8kn8do.s4.Patrick.Schoenbach@workstation.int.solidsoft.iksys.de...
> On Sat, 17 Jun 2000 09:32:08 GMT,
> Thaddeus L. Olczyk <olczyk@interaccess.com> wrote:
>
> >On Thu, 15 Jun 2000 22:11:34 -0400, Andrew Hunt <andy@Toolshed.Com>
> >wrote:
> >>
> >>I disagree strongly.  While Meyer is an advocate of static typing, I
> >>see no reason that DBC cannot be effective in a dynamically typed
> >>environment -- in fact, it seems to me that DBC could be even *more*
> >>useful in a dynamic environment than in a static one.
>
> I agree with Andy here. IMHO DBC and typing are two different things. We
> Eiffelists believe that static typing is better suited to create robust
> and correct systems. This is heavily argued thought, and we should not
> start another "static vs dynamic typing" war.
>
> But DBC is not directly related to the typing issue. Even in Eiffel,
> assertion checking is done completely at *run time*. So, I see no
> problems either to implement DBC in a dynamic environment.

i agree with you completely on the value of dbc and static typing, but my
view about their relation is somewhat different.

i see static type information as the statically verifiable part of dbc -- it
_is_ part of the contract, but because of the nature of the information it
may be treated differently, and used for different purposes. clearly, this
view is not quite consistent with covariant inheritance, and thus with the
implementation in eiffel, but wouldn't this be the most natural way of
looking at type information and other properties of classes/objects?

best regards,

-- j