Re: Representation clause for enumeratives

["M. Kotiaho" <kotiaho@m_a_i_l.com>]

Robert Dewar wrote:

> In article <95u470$ho1$1@nnrp1.deja.com>,
>   Sandro Binetti <sandrobinetti@my-deja.com> wrote:
> > In article <95tre2$f33@news.kvaerner.com>,
> >   "Tarjei T. Jensen" <tarjei.jensen@kvaerner.com> wrote:
> > > Have you tried to insert a size directive. e.g
> > >
> > > type TYP_ENUM is (A,B,C);
> > >
> > > for TYP_ENUM'size use 32;
> >
> > Done. But the problem is still the same ...
> > Why?
>
> Presumably a capacity limitation in the compiler you are
> using, not a terribly justifiable one, so you should bring
> this to the attention of the vendor. Most likely the decision
> is to use a signed 32-bit integer to represent enumerations,
> which as you see in this case can be an annoying restriction.
>
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> http://www.deja.com/

Indeed, GNAT on WinNT (Pentium-II) will allow the following:

    type TYP_ENUM is (A,B,C);

    for TYP_ENUM use(
       -16#8000000000000000#,
        16#00000002#,------#
        16#7FFFFFFFFFFFFFFF#  -- <<<<< NOTICE THIS VALUE !!!
 );

Apparently, GNAT is using a signed 64-bit integer.

Incidently, both compilers are sticking to the
"at least" portion of the implementation advice -- they
just define System.Min_Int and System.Max_Int differently:

(Copied from Lutz Donnerhacke's post)
>Implementation Advice
> 9. The recommended level of support for
enumeration_representation_clauses is:
>      1. An implementation should support at least the internal codes
in the
>         range System.Min_Int..System.Max_Int. An implementation need
not
>         support enumeration_representation_clauses for boolean types.

Markku Kotiaho