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From: Robert A Duff <bobduff@shell01.TheWorld.com>
Newsgroups: comp.lang.ada
Subject: Re: 'Protected' abstract subprograms
Date: Thu, 16 Jan 2014 20:49:28 -0500
Organization: The World Public Access UNIX, Brookline, MA
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Date: 2014-01-16T20:49:28-05:00
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AdaMagica <christ-usch.grein@t-online.de> writes:

> On Thursday, January 16, 2014 1:51:31 AM UTC+1, Robert A Duff wrote:
>> The only case I know of where the code in a package private part can affect the
>> legality of code outside that package is this:
>>
>>     package Recursive_Types is
>>
>>        type T1 is private;
>>
>>        package Nested is
>>           type T2 is private;
>>        private
>>           type T2 is record
>>              X: T1;
>
> I think this is illegal since it would freeze T1. Wouldn't it?

No, declaring an object of type T1 would freeze T1, but a component
does not.

The freezing rules make my brain hurt.  Even though I had a hand in
writing them!  ;-)

A better-designed language would not have anything like freezing rules.

>>           end record;
>>        end Nested;
>>
>>     private
>> 
>>        type T1 is record

- Bob