To: tews@tcs.inf.tu-dresden.de
Subject: Re: grammar for class types, reraised
In-Reply-To: Your message of "Tue, 22 Jun 1999 19:00:22 +0200"
<199906221700.TAA21025@ithif20.inf.tu-dresden.de>
Message-Id: <19990623104049R.garrigue@kurims.kyoto-u.ac.jp>
Date: Wed, 23 Jun 1999 10:40:49 +0900
From: Jacques GARRIGUE <garrigue@kurims.kyoto-u.ac.jp>
From: Hendrik Tews <tews@tcs.inf.tu-dresden.de>
> From: Jerome Vouillon <Jerome.Vouillon@inria.fr>
> > 2. Why is it not possible to add type constraints to the first
> > kind of type abbreviation, like in
> >
> > class type ['a] c = ['a, string] a constraint 'a = int;;
>
> There is no real reason. I think I could add this quite easily to the
> language if you need this.
In fact, you can already do that:
class type ['a, 'b] a = object method m : 'a -> 'b end
class type ['a] c = object
inherit ['a,string] a
constraint 'a = int
end
Remark also that inheritance at the type level does not presuppose
inheritance at the value level, so this should be general enough.
Jacques
---------------------------------------------------------------------------
Jacques Garrigue Kyoto University garrigue at kurims.kyoto-u.ac.jp
<A HREF=http://wwwfun.kurims.kyoto-u.ac.jp/~garrigue/>JG</A>
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