From: ada_student@yahoo.com
Subject: Re: types and subtypes
Date: 13 Mar 2006 10:08:45 -0800
Date: 2006-03-13T10:08:45-08:00 [thread overview]
Message-ID: <1142273325.634632.41020@j52g2000cwj.googlegroups.com> (raw)
In-Reply-To: bjr3vd.ep4.ln@hunter.axlog.fr
> Because they are of the same *type*. A subtype does not declare a
> different type, only a restriction (a *constraint*) on the allowed
> values. Since the types are the same, the declaration is OK.
>
Then Ada's definition of a type is different from other languages.
A type also defines the set of values that an object can have.
If an Ada subtype adds a constraint to an Ada type, then the
subtype is a type that is a derivative(derivative as in the Ada
sense) of the Ada type and is different from that type.
[I know you can say "type T2 is new T1 ..." in Ada to denote
derivation]
Why doesnt Ada subtyping also denote derivation as in the
sense C++ base classes and derived classes do?
Why was Ada's subtyping defined to exclude derivation?
next prev parent reply other threads:[~2006-03-13 18:08 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-13 12:07 types and subtypes ada_student
2006-03-13 13:20 ` Jean-Pierre Rosen
2006-03-13 18:08 ` ada_student [this message]
2006-03-13 18:17 ` Ed Falis
2006-03-13 19:14 ` Larry Kilgallen
2006-03-13 19:42 ` Martin Krischik
2006-03-13 20:22 ` Wilhelm Spickermann
2006-03-14 8:47 ` Dmitry A. Kazakov
2006-03-14 14:39 ` Jean-Pierre Rosen
2006-03-17 1:24 ` Peter C. Chapin
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