Re: Enumeration representation clause surprise.

[Markus Schoepflin <nospam@no.spam>]

Niklas Holsti wrote:
> Adam Beneschan wrote:
> 
>> ... technically it may be that
>> the RM doesn't require the specified representation to be honored for
>> *any* objects, stand-alone or component.  At least I couldn't find
>> anything specific, unless this is "generally implied" by the whole
>> chapter or by 13.1.  It may be that it's legal for an implementation
>> to accept an enumeration representation clause and then never apply
>> it.
> 
> There's a "Note" in RM13.4(11/1) that says "Unchecked_Conversion may be 
> used to query the internal codes used for an enumeration type". I don't 
> know if "Notes" are normative parts of the standard. It would be 
> interesting to know what Unchecked_Conversion gives for the 1-bit record 
> component in Markus' problematic record. If it gives 0 and 1, as 
> encoded, and not 1 and 2, as required in the enumeration representation 
> clause, it would seem to violate this "Note".

Both GNAT and Dec Ada return 1 and 2 for both A1 and A2, so they are 
correctly debiasing when explicitly asked for the internal representation.

Markus