From: Robert A Duff <bobduff@world.std.com>
Subject: Re: Naming of Tagged Types and Associated Packages
Date: 1998/08/13
Date: 1998-08-13T00:00:00+00:00 [thread overview]
Message-ID: <wccd8a4wm5g.fsf@world.std.com> (raw)
In-Reply-To: Pine.BSF.3.96.980811212848.17710A-100000@shell5.ba.best.com
Brian Rogoff <bpr@shell5.ba.best.com> writes:
> I think if you keep type information around at run time, you've sacrificed
> some optimization, right?
I don't think so. For example, consider "Mumble(T'Class(X));" in Ada,
or X.Mumble in Eiffel. Both dispatch to the appropriate implementation
of Mumble at run time, and both need to have "type information" around
at run time to do so. If that type info weren't automatically kept
around, the programmer would have to keep that same information
explicitly. Note that the type info isn't being used here to perform
run-time type checking; in both languages, there's guaranteed to be an
appropriate Mumble to call.
> I agree that Eiffel's built in assertion mechanisms are very nice, and
> more powerful than what we have in Ada. I also think that external tools
> could provide many of the same advantages, and maybe even provide more.
I'd be interested in seeing a design for such external tools.
> Sure, but different groups can develop independent modules in Ada, compile
> pieces independently, and link them together in the end and be sure that
> the result contains no type violations (there could be other violations,
> like range violations, which would correspond to violated assertions in
> Eiffel). This is not true of Eiffel.
It seems sort of silly to say, "Language X catches all *type* errors at
compile time, but of course there are other errors that are caught only
at run time", since the language definition defines what's a "type
error" and what's an "other error". Eg Ada catches variant record
errors at run time. One could reasonably call those "type errors", but
the language definition says they're merely "constraint check failures".
I can easily define a language that catches *all* type errors at compile
time, merely by defining "type error" to match what happens to be caught
at compile time.
Some folks would consider "divide by zero" to be a type error.
But most languages catch it at run time. I could force it to be caught
at compile time, but it might not improve the programming language.
- Bob
--
Change robert to bob to get my real email address. Sorry.
next prev parent reply other threads:[~1998-08-13 0:00 UTC|newest]
Thread overview: 138+ messages / expand[flat|nested] mbox.gz Atom feed top
1998-07-16 0:00 Naming of Tagged Types and Associated Packages taashlo
1998-07-25 0:00 ` Matthew Heaney
1998-07-25 0:00 ` Jean-Pierre Rosen
1998-07-25 0:00 ` Brian Rogoff
1998-07-26 0:00 ` Matthew Heaney
1998-07-26 0:00 ` Matthew Heaney
1998-07-26 0:00 ` nabbasi
1998-07-26 0:00 ` Robert Dewar
1998-07-26 0:00 ` Matthew Heaney
1998-07-27 0:00 ` Jean-Pierre Rosen
1998-07-28 0:00 ` Matthew Heaney
1998-07-28 0:00 ` Jean-Pierre Rosen
1998-07-28 0:00 ` dennison
1998-07-29 0:00 ` Jean-Pierre Rosen
1998-07-29 0:00 ` dennison
1998-07-29 0:00 ` Jean-Pierre Rosen
1998-07-30 0:00 ` dennison
1998-07-30 0:00 ` Jean-Pierre Rosen
1998-07-29 0:00 ` Robert I. Eachus
1998-07-30 0:00 ` Jean-Pierre Rosen
1998-07-30 0:00 ` Robert I. Eachus
1998-07-31 0:00 ` Jean-Pierre Rosen
1998-07-31 0:00 ` Robert I. Eachus
1998-08-01 0:00 ` Jean-Pierre Rosen
1998-08-04 0:00 ` Matthew Heaney
1998-08-04 0:00 ` Jean-Pierre Rosen
1998-08-10 0:00 ` Robert I. Eachus
1998-07-30 0:00 ` Matthew Heaney
1998-07-27 0:00 ` dennison
1998-07-27 0:00 ` Stephen Leake
1998-07-27 0:00 ` dennison
1998-07-27 0:00 ` Brian Rogoff
1998-07-28 0:00 ` dennison
1998-07-28 0:00 ` Brian Rogoff
1998-07-28 0:00 ` dennison
1998-07-29 0:00 ` Matthew Heaney
1998-07-29 0:00 ` Chris Brand
1998-07-30 0:00 ` Matthew Heaney
1998-07-30 0:00 ` dennison
1998-07-30 0:00 ` Matthew Heaney
1998-07-30 0:00 ` dennison
1998-08-01 0:00 ` Simon Wright
1998-08-02 0:00 ` Matthew Heaney
1998-08-03 0:00 ` dennison
1998-08-03 0:00 ` Matthew Heaney
1998-08-04 0:00 ` dennison
1998-08-04 0:00 ` Jean-Pierre Rosen
1998-08-04 0:00 ` Brian Rogoff
1998-08-05 0:00 ` Don Harrison
1998-08-05 0:00 ` Matthew Heaney
1998-08-07 0:00 ` Don Harrison
1998-08-13 0:00 ` Robert A Duff
1998-08-14 0:00 ` Don Harrison
1998-08-14 0:00 ` adam
1998-08-05 0:00 ` Brian Rogoff
1998-08-07 0:00 ` doylep
1998-08-07 0:00 ` Brian Rogoff
1998-08-08 0:00 ` Matthew Heaney
1998-08-10 0:00 ` doylep
1998-08-10 0:00 ` Brian Rogoff
1998-08-10 0:00 ` John Volan
1998-08-10 0:00 ` John Volan
1998-08-11 0:00 ` doylep
1998-08-11 0:00 ` Brian Rogoff
1998-08-13 0:00 ` Robert A Duff [this message]
1998-08-13 0:00 ` Brian Rogoff
1998-09-01 0:00 ` Matthew Heaney
1998-09-01 0:00 ` Dale Stanbrough
1998-09-01 0:00 ` Matthew Heaney
1998-09-01 0:00 ` Bob Collins
1998-09-02 0:00 ` Matthew Heaney
1998-09-04 0:00 ` John G. Volan
1998-08-11 0:00 ` Don Harrison
1998-08-11 0:00 ` Pat Rogers
1998-08-11 0:00 ` Don Harrison
1998-09-01 0:00 ` Matthew Heaney
1998-08-13 0:00 ` Robert A Duff
1998-08-13 0:00 ` Brian Rogoff
1998-08-15 0:00 ` Don Harrison
1998-08-15 0:00 ` Jean-Pierre Rosen
1998-08-18 0:00 ` Don Harrison
1998-08-14 0:00 ` Don Harrison
1998-08-17 0:00 ` doylep
1998-08-19 0:00 ` Don Harrison
1998-08-12 0:00 ` Don Harrison
1998-08-08 0:00 ` Matthew Heaney
1998-08-08 0:00 ` John G. Volan
1998-08-09 0:00 ` Matthew Heaney
1998-08-10 0:00 ` John G. Volan
1998-08-11 0:00 ` Don Harrison
1998-08-11 0:00 ` geoff
1998-08-11 0:00 ` John Volan
1998-08-31 0:00 ` Matthew Heaney
1998-08-31 0:00 ` Tucker Taft
1998-09-06 0:00 ` John G. Volan
1998-09-06 0:00 ` Matthew Heaney
1998-09-04 0:00 ` John G. Volan
1998-09-06 0:00 ` Matthew Heaney
1998-09-06 0:00 ` John G. Volan
1998-09-06 0:00 ` John G. Volan
1998-09-06 0:00 ` Brian Rogoff
1998-09-06 0:00 ` John G. Volan
1998-09-07 0:00 ` Brian Rogoff
1998-09-07 0:00 ` John G. Volan
1998-09-16 0:00 ` Matthew Heaney
1998-09-04 0:00 ` John G. Volan
1998-09-05 0:00 ` John G. Volan
1998-09-06 0:00 ` Matthew Heaney
1998-09-06 0:00 ` Matthew Heaney
1998-09-04 0:00 ` John G. Volan
1998-09-05 0:00 ` Matthew Heaney
1998-09-05 0:00 ` John G. Volan
1998-09-05 0:00 ` John G. Volan
1998-09-05 0:00 ` John G. Volan
1998-08-11 0:00 ` doylep
1998-08-07 0:00 ` Don Harrison
1998-08-05 0:00 ` Static Polymorphism (Was Re: Naming of Tagged Types...) Brian Rogoff
1998-08-06 0:00 ` Matthew Heaney
1998-08-06 0:00 ` Brian Rogoff
1998-07-28 0:00 ` Naming of Tagged Types and Associated Packages Brian Rogoff
1998-07-29 0:00 ` Matthew Heaney
1998-07-29 0:00 ` Brian Rogoff
1998-07-28 0:00 ` Norman H. Cohen
1998-07-28 0:00 ` Stephen Leake
1998-07-28 0:00 ` Matthew Heaney
1998-07-28 0:00 ` Matthew Heaney
1998-07-28 0:00 ` Jean-Pierre Rosen
1998-07-28 0:00 ` Matthew Heaney
1998-07-28 0:00 ` dennison
1998-07-29 0:00 ` Matthew Heaney
1998-07-30 0:00 ` Robert Dewar
1998-07-30 0:00 ` Matthew Heaney
1998-08-06 0:00 ` Robert A Duff
1998-08-06 0:00 ` Matthew Heaney
1998-08-06 0:00 ` Tucker Taft
1998-08-31 0:00 ` Matthew Heaney
-- strict thread matches above, loose matches on Subject: below --
1998-07-26 0:00 tmoran
1998-07-27 0:00 ` dennison
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