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From: danmcleran@hotmail.com
Newsgroups: comp.lang.ada
Subject: Possible Ada deficiency?
Date: 31 Dec 2004 11:06:29 -0800
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Date: 2004-12-31T11:06:29-08:00
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I would like to know if anyone else thinks that the inability to hide
private information from child packages is a deficiency in Ada95. I am
discussing ways to do this on another thread, (See Private area and
child packages), but it seems wrong that one has to go through a bunch
of machinations to do something like this. Wouldn't a language
construct for this be advantageous?

In C++ and Java, no private data can be seen by child classes. I think
that Ada would benefit from extending its information hiding
capabilities by allowing a package writer to conceal type information
from child packages.

What if Ada had a keyword, I've chosen 'concealed' for the sake of
discussion, to indicate that the implementation of a type was not
visible to the outside world (including child packages). Something like
this:

--This is not Ada!

package Some_Package is
type Not_So_Secret_Type is private;   -- Child packages can see the
details
type Super_Secret_Type  is concealed; -- Hidden from everyone
private
--child packages have full visibility
concealed
--not even child packages can see here
end Some_Package;