Re: Ocaml 2 object system origins

From: Jerome Vouillon (Jerome.Vouillon@inria.fr)
Date: Fri Sep 10 1999 - 16:05:19 MET DST


Date: Fri, 10 Sep 1999 16:05:19 +0200
From: Jerome Vouillon <Jerome.Vouillon@inria.fr>
To: John Prevost <prevost@maya.com>, caml-list@inria.fr
Subject: Re: Ocaml 2 object system origins
In-Reply-To: <m33dws495j.fsf@isil.maya.com>; from John Prevost on Mon, Sep 06, 1999 at 06:38:32AM -0400

On Mon, Sep 06, 1999 at 06:38:32AM -0400, John Prevost wrote:
> I just came across the paper "Typing in object-oriented languages:
> Achieving expressiveness and safety" by Kim Bruce, and was struck,
> once I referred back to the O'Caml documentation on the new object
> system, by the similarities.
>
> So, I was just wondering whether the features of the new object system
> are based on this paper, a predecessor of this paper, or perhaps the
> language LOOM, which apparently shares syntax with the examples in the
> paper.

The two object systems was designed independently and are actually
very different, even though they seem to have roughly the same
expressive power. For instance, O'Caml has no notion of "MyType" and
does not use a matching relation (<#). But these two notions can more
or less be expressed using recursive types and type instantiation.

> (The presence of # types seems too much to be chance.)

Indeed, I chose this syntax because the # abbreviations have
(very) roughly the same meaning as the # types of Kim Bruce.

-- Jérôme



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