Re: Assigning a "subclass" instance to a "superclass" variable

[Simon Wright <simon@pushface.org>]

deuteros <deuteros@xrs.net> writes:

> On Fri 06 Apr 2012 05:50:18p, Simon Wright <simon@pushface.org> wrote in
> news:m2ty0wh6n9.fsf@pushface.org: 
>
>>    with Statements;
>>    package Expressions is
>>       type Expression is new Statements.Statement with record
>>          ...
>>       end record;
>>       function Execute (Skip : Boolean; S : Expression) return Integer;
>>    end Expressions;
>> 
>> or
>> 
>>    package Statements.Expressions is
>>       type Expression is new Statement with record
>>          ...
>>       end record;
>>       function Execute (Skip : Boolean; S : Expression) return Integer;
>>    end Statements.Expressions;
>> 
>> The second form is good if the full declaration of Statement is in
>> the private part of Statements, since child packages can see the
>> private parts of their parents.
>
> Okay, so would I need to put tokens and executedtokens in Expression's
> record as well or would it somehow inherit them from Statements?

They are inherited. See the Ada 95 Rationale:
http://www.adaic.org/resources/add_content/standards/95rat/rat95html/rat95-p1-2.html#1