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From: "Matthew Heaney" <matthew_heaney@acm.org>
Subject: Re: tagged types extensions - language design question
Date: 2000/02/01
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In article <38970C27.5362779A@earthlink.net> , Charles Hixson 
<charleshixsn@earthlink.net>  wrote:

> I can't speak for him (Vladimir Olensky) but my reason is so that I need to
> keep track of fewer names.  I frequently pick up projects for short periods of
> time, and then put them down for several months before the next time that I
> pick them up.  If I have to keep track of fewer names then I find it easier to
> reposition myself in the project.  Of course, if anything was ever really
> completed, then the private sections would never need to be thought about
> again.  This, however, doesn't seem to map well into my perceived reality.

There are no names that you need to remember.

Suppose I declare an abstraction comprising some public and some private
attributes, like this:

package P is

  type T_Public is abstract tagged record
    Public_Attribute : Public_Attribute_Type;
  end record;

  type T is new T_Public with private;
...
end P;


That type T_Public is part of the hierarchy is irrelevant.  This just
happens to be the syntax for declaring public attributes in type T,
which is the only type you care about.