From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: User-defined type attributes
Date: Sat, 15 Mar 2008 10:33:38 +0100
Date: 2008-03-15T10:33:38+01:00 [thread overview]
Message-ID: <13vp773bcnkwf.7zfswly78jlo$.dlg@40tude.net> (raw)
In-Reply-To: frffdo$2jo$1@jacob-sparre.dk
On Fri, 14 Mar 2008 22:04:53 -0500, Randy Brukardt wrote:
> Not if you need other generic parameters along with the type. And this is a
> way to do mixins, which otherwise can't be done in Ada 95 because type can't
> derive from a class-wide type:
>
> generic
> type S is new T with private;
> package Foo is
> type New_S is new S with private;
> procedure New_Operation (Op : in out New_S);
> end Foo;
>
> It's a nice way to add persistence, for instance. (Interfaces only allow you
> to add, umm, interfaces, not code.)
Speaking of language enhancements proper multiple inheritance would be a
better way to do this.
But actually I would like to have "supertypes" in order to be able to add
interfaces and code to existing types:
type T is ...; -- Defined independently on Persistent
type Persistent is abstract...; -- Oops, we forgot to do it before T
type Bridge is new Persistent and old T; --- (:-))
Bridge is a subtype of Persistent and a supertype of T. This injects
Bridge's implementation of Persistent into T within Bridge's scope.
--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
next prev parent reply other threads:[~2008-03-15 9:33 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-12 18:58 User-defined type attributes Eric Hughes
2008-03-12 21:23 ` Dmitry A. Kazakov
2008-03-13 18:32 ` Eric Hughes
2008-03-13 19:58 ` Dmitry A. Kazakov
2008-03-14 1:46 ` Randy Brukardt
2008-03-14 1:46 ` Randy Brukardt
2008-03-14 9:00 ` Dmitry A. Kazakov
2008-03-14 14:36 ` User-defined type attributes (replacing genericity) Georg Bauhaus
2008-03-15 3:04 ` User-defined type attributes Randy Brukardt
2008-03-15 9:33 ` Dmitry A. Kazakov [this message]
2008-03-14 14:31 ` User-defined type attributes (replacing genericity) Georg Bauhaus
2008-03-14 14:48 ` Dmitry A. Kazakov
2008-03-14 17:51 ` Eric Hughes
2008-03-14 18:58 ` Dmitry A. Kazakov
2008-03-14 20:19 ` Eric Hughes
2008-03-15 4:01 ` Randy Brukardt
2008-03-14 16:58 ` Georg Bauhaus
2008-03-14 18:39 ` Dmitry A. Kazakov
2008-03-15 9:39 ` Dmitry A. Kazakov
2008-03-14 1:46 ` User-defined type attributes Randy Brukardt
2008-03-14 3:55 ` Eric Hughes
2008-03-14 9:01 ` Dmitry A. Kazakov
2008-03-14 18:04 ` Eric Hughes
2008-03-14 1:46 ` Randy Brukardt
2008-03-14 4:41 ` Eric Hughes
2008-03-15 3:20 ` Randy Brukardt
2008-03-17 4:38 ` Eric Hughes
2008-03-17 21:03 ` Randy Brukardt
2008-03-17 21:58 ` Eric Hughes
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