Re: Representation clause for enumeratives

[Robert Dewar <dewar@gnat.com>]

In article <Ndyg6.1048$y03.96769@news.flash.net>,
  "Ken Garlington" <Ken.Garlington@computer.org> wrote:
> I don't know if either behavior is considered "wrong" by the
standard. I'm
> not comfortable with the GNAT behavior, since it treats
16#8000_0000# as a
> legal 32-bit integer value, although it is not in the range
Standard.Integer
> on the same machine.

Who says that the range of enumeration values is restricted
to Standard.Integer, in fact no one says it, and the RH in
the RM encourages you to go up to maxint which for GNAT
is 2**63-1. Why you should be uncomfortable because GNAT
does NOT implement a limitation which

(a) would not be helpful
(b) would violate implementation advice

is puzzling indeed!

> This just encourages the confusion between hex numbers
> and bit-patterns. I do see the utility of doing it this way,
> however.

I don't understand the confusion. GNAT chooses a large enough
signed or unsigned integer type to cover the range of values
provided.

Note that 16#8000_0000# is the number 2**32, it is a POSITIVE
number, nothing at all to do with the largest negative number.
I think the confusion is coming from the use of base 16, and
suddenly that is translating into bit patterns in your mind???

Any time you write 16#8000_0000# in your program, you could
equally well write 2147483648. The meaning is 100% identical.
If the first looks like a bit pattern to you, and the second
looks like an integer, then that's your confusion, not Ada's
:-)


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