From: Robert A Duff <bobduff@world.std.com>
Subject: Re: Subverting 'Access for Sub-programs
Date: 1999/08/06
Date: 1999-08-06T00:00:00+00:00 [thread overview]
Message-ID: <wccu2qdnidg.fsf@world.std.com> (raw)
In-Reply-To: 7ocrji$scl$1@nnrp1.deja.com
adam@irvine.com writes:
> Actually, posts on this thread that I read after writing the above,
> along with some lookup in DejaNews, have mostly answered my question.
> However, the discussions I found in DejaNews mentioned proposals to put
> restrictions on assignment of these types, but not runtime checks. Was
> anything like this seriously considered?
There was one proposal that involved run-time checks (see my other
posting), but I'm not sure it matches the kinds of run-time checks
you're thinking of. I don't think anybody ever proposed a feature where
you could form a pointer to a (possibly-nested) subprogram, and then
check the validity of this pointer at the call site. Such a feature
would be difficult to implement efficiently. In fact, if you're going
*that* far, I suspect you might as well go all the way to full closures,
as in various Lisp-style languages.
>...Would it be simpler to
> implement than the other solutions (for implementations that use
> displays)?
Well, the totally-unchecked version of downward closures causes
difficulty for display-based implementations, so it's hard to see how
any version with checks (compile time or run time) could make things
easier.
- Bob
--
Change robert to bob to get my real email address. Sorry.
next prev parent reply other threads:[~1999-08-06 0:00 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-08-03 0:00 Subverting 'Access for Sub-programs Anton Gibbs
1999-08-03 0:00 ` tmoran
1999-08-03 0:00 ` Steve Doiel
1999-08-03 0:00 ` Ted Dennison
1999-08-03 0:00 ` David C. Hoos, Sr.
1999-08-05 0:00 ` Robert A Duff
1999-08-03 0:00 ` Michael F. Yoder
1999-08-03 0:00 ` Brian Rogoff
1999-08-04 0:00 ` Robert Dewar
1999-08-04 0:00 ` Robert A Duff
1999-08-04 0:00 ` Robert Dewar
1999-08-04 0:00 ` Anton Gibbs
1999-08-04 0:00 ` Robert A Duff
1999-08-04 0:00 ` Brian Rogoff
1999-08-05 0:00 ` tmoran
1999-08-05 0:00 ` Robert Dewar
1999-08-05 0:00 ` Ray Blaak
1999-08-06 0:00 ` Jean-Pierre Rosen
1999-08-06 0:00 ` Hyman Rosen
1999-08-07 0:00 ` Florian Weimer
1999-08-06 0:00 ` Robert Dewar
1999-08-06 0:00 ` Robert A Duff
1999-08-08 0:00 ` Brian Rogoff
1999-08-09 0:00 ` Robert A Duff
1999-08-10 0:00 ` Brian Rogoff
1999-08-09 0:00 ` Tucker Taft
1999-08-05 0:00 ` Aidan Skinner
1999-08-05 0:00 ` Anton Gibbs
1999-08-04 0:00 ` Jean-Pierre Rosen
1999-08-04 0:00 ` Brian Rogoff
1999-08-05 0:00 ` Jean-Pierre Rosen
1999-08-05 0:00 ` adam
1999-08-05 0:00 ` adam
1999-08-06 0:00 ` Robert A Duff [this message]
1999-08-06 0:00 ` adam
1999-08-09 0:00 ` Robert A Duff
1999-08-09 0:00 ` Mark Biggar
1999-08-05 0:00 ` Robert Dewar
1999-08-05 0:00 ` What is a Display ? (was: Subverting 'Access for Sub-programs) Larry Kilgallen
1999-08-05 0:00 ` Hyman Rosen
1999-08-06 0:00 ` Robert Dewar
1999-08-06 0:00 ` Robert Dewar
1999-08-05 0:00 ` Subverting 'Access for Sub-programs Robert A Duff
1999-08-05 0:00 ` Brian Rogoff
1999-08-06 0:00 ` Robert Dewar
1999-08-09 0:00 ` Tucker Taft
1999-08-10 0:00 ` Robert Dewar
1999-08-11 0:00 ` Dmitry A. Kazakov
1999-08-11 0:00 ` Robert Dewar
1999-08-12 0:00 ` Dmitry A. Kazakov
1999-08-14 0:00 ` Robert Dewar
1999-08-16 0:00 ` Dmitry A. Kazakov
1999-08-11 0:00 ` Richard D Riehle
1999-08-11 0:00 ` Tucker Taft
1999-08-13 0:00 ` Robert Dewar
1999-08-13 0:00 ` Robert Dewar
1999-08-13 0:00 ` Brian Rogoff
1999-08-11 0:00 ` Robert A Duff
1999-08-11 0:00 ` Robert Dewar
1999-08-05 0:00 ` tmoran
1999-08-06 0:00 ` Robert A Duff
1999-08-05 0:00 ` Robert Dewar
1999-08-06 0:00 ` Brian Rogoff
1999-08-07 0:00 ` Gautier
1999-08-05 0:00 ` Robert A Duff
1999-08-05 0:00 ` Robert Dewar
1999-08-05 0:00 ` Brian Rogoff
1999-08-05 0:00 ` Steve Quinlan
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