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Re: Object Class and Data Type

From: D Guntermann <guntermann_at_hotmail.com>
Date: Tue, 30 Mar 2004 23:29:09 GMT
Message-ID: <HvEx8L.9tC@news.boeing.com>

"Tom Hester" <$$tom_at_metadata.com> wrote in message news:d2b19$406990ec$45033832$24651_at_msgid.meganewsservers.com...
> Of course you are right. The purpose of class and type are entirely
> different. A class hierarchy is intended to relate entities based on
common
> behavior; however, a set of data types is intended to elaborate the
> differences between sets of values.

So I guess real numbers, rational numbers, and integers are not part of the same class hierarchy since they are data *types* versus your precious classes. What kind of reasoning is this? There are still basic properties of numbers shared, whether its called class or type.

Isn't the set of engineer objects in some context a subset of person objects? The set of values are different based on semantics and rules, but they are drawn from the same generalized set - the same as numbers.

So, for example, it is common for a
> class hierarchy to have a single root; often called object or entity. But
> data types rarely if ever inherit from a single basic data type.
> Furthermore, class itself is typically defined as an object with certain
> behaviors. On the other hand, one never sees data type, a base type,
> defined as a data type!

You are getting data type and built-in data type confused. You are also confusing low-level constructs with higher levels of abstraction.

Received on Tue Mar 30 2004 - 17:29:09 CST

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