Re: Representation clause for enumeratives

["Ken Garlington" <Ken.Garlington@computer.org>]

"Robert Dewar" <dewar@gnat.com> wrote in message
news:967ar9$sq7$1@nnrp1.deja.com...
: In article <OExh6.5397$y03.334735@news.flash.net>,
:   "Ken Garlington" <Ken.Garlington@computer.org> wrote:
: > For example, I'd argue that -16#FFFF_FFFF# .. -1 is both
: > "representable" in 32 bits and in the range System.Min_Int ..
: > System.Max_Int.
:
: > Words about treating a set with no negative values as
: > unsigned values, and as unbiased signed values otherwise
: > would have been clearer to me.
:
: Don't hesitate to make documentation suggestions, many
: improvements to the documentation come from suggestions
: sent to report@gnat.com.
:
: In this particular case, the RM of course does not allow
: biasing of representations when an enumeration representation
: clause is present, since this is one of the few (really the
: only) case where the RM has something to say about
: representation, and indeed the ACVC tests (I wrote the relevant
: ones :-) test this by doing unchecked conversion.

Would "biased" be the correct term for a representation of -16#FFFF_FFFF#
.. -1, where you use two's complement convention to store all negative
numbers (and ignore overflow)?

I'm also curious about how the ACVC tests use unchecked conversion in a
portable manner in this case. In particular, what are you converting _to_?

: But it never hurts to emphasize things in the documentation,
: so I agree it would be helpful to point out that biased
: representations cannot be used for enumeration types!
:
:
: Sent via Deja.com
: http://www.deja.com/