Re: Representing data differently

["Martin Krischik" <Martin.Krischik@T-Online.de>]

On Sat, 22 Feb 2003 14:09:09 +0000, Robert A Duff wrote:

> "Martin Krischik" <Martin.Krischik@T-Online.de> writes:
> 
>>     for
>>         State
>>     use record
>>         uninitialized   at 0 range 0..0;  
>>         on              at 0 range 1..1;    
>>         writeLineNumber at 0 range 2..2;   
>>         writePrefix     at 0 range 3..3;   
>>     end record;
>> 
>> -- snap
>> 
>> The first statement defines the record, the second defines the layout.
>> Nothing stops you from placing two record elements at the same position.
> 
> Actually, 13.5.1(11) makes it illegal.
 
True.

--
(11)
At most one component_clause is allowed for each component of the type,
including for each discriminant (component_clauses may be given for some,
 all, or none of the components). Storage places within a component_list
shall not overlap, unless they are for components in distinct variants of
the same variant_part. 
--

So you have to combine the record layout with a variant record. Which make
the original request quite complex to implement. But then the C code wan't
easy either.

with Regards

Martin

-- 
Martin Krischik
mailto://Martin@krischik.com
http://www.ada.krischik.com