From: Jerome Vouillon <Jerome.Vouillon@inria.fr>
To: Markus Mottl <mottl@miss.wu-wien.ac.at>
Cc: OCAML <caml-list@inria.fr>
Subject: Re: subtyping and inheritance
Date: Wed, 27 Jan 1999 15:18:27 +0100 [thread overview]
Message-ID: <19990127151827.16711@pauillac.inria.fr> (raw)
In-Reply-To: <199901250008.BAA29432@miss.wu-wien.ac.at>; from Markus Mottl on Mon, Jan 25, 1999 at 01:08:30AM +0100
On Mon, Jan 25, 1999 at 01:08:30AM +0100, Markus Mottl wrote:
[...]
> So far it seems that things would be unsafe with covariance. But now,
> Castagna answers my (former) question, whether making "reappear" methods
> from ancestors would be safe: it is...
>
> The paper looked difficult at first, but turned out to be surprisingly
> easy to read: Castagna makes the theorie very intuitively clear with his
> examples of classes "2DPoint" and "3DPoint" and how methods are chosen
> in the different models.
>
> The record based method (as found in OCAML - the object (record)
> determines, which method is selected, arguments are not considered)
> can be obviously extended to support covariance.
However, it is not possible to apply this extension to Ocaml. Indeed,
it requires that methods are chosen depending on the dynamic type of
their arguments. But this information is not available in Ocaml.
There are also difficulties for type inference.
-- Jérôme
next prev parent reply other threads:[~1999-01-27 18:28 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-01-11 18:52 Markus Mottl
1999-01-15 15:02 ` Jerome Vouillon
1999-01-15 17:37 ` Markus Mottl
1999-01-18 19:55 ` Jerome Vouillon
1999-01-18 21:18 ` Markus Mottl
1999-01-20 11:50 ` Hendrik Tews
1999-01-25 0:08 ` Markus Mottl
1999-01-25 15:06 ` Musings on Obj.magic (Was: subtyping and inheritance) David Monniaux
1999-01-27 14:18 ` Jerome Vouillon [this message]
1999-01-27 14:45 ` subtyping and inheritance Markus Mottl
1999-01-28 19:40 ` Hendrik Tews
1999-01-27 14:28 ` Jerome Vouillon
1999-04-15 12:18 Giuseppe Castagna
1999-04-15 16:02 ` Markus Mottl
1999-04-20 12:38 ` Didier Remy
1999-04-20 15:06 ` Giuseppe Castagna
1999-04-21 12:18 ` Didier Remy
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=19990127151827.16711@pauillac.inria.fr \
--to=jerome.vouillon@inria.fr \
--cc=caml-list@inria.fr \
--cc=mottl@miss.wu-wien.ac.at \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox