Re: SOLVED! Decoupled Mutual Recursion Challenger

[bobduff@dsd.camb.inmet.com (Bob Duff)]

In article <1994Oct17.154812.9104@swlvx2.msd.ray.com>,
John Volan <jgv@swl.msd.ray.com> wrote:
>In article <1994Oct12.224944.25566@swlvx2.msd.ray.com> I (John Volan) wrote:
>> (Er ... I've been scouring the RM9X 5.0 and much to my surprise I can't
>> seem to find positive confirmation for the fact that System.Address will
>> have the same bit-representation as access types.  Tucker, if you're
>> listening, can you give me a hand here?)
>
>Actually, there wasn't any need to involve System.Address after all.
>A better solution would be to just declare Identity.Value as an access
>type pointing to some "dummy" designated type. 

There is no requirement that type Address have the same representation
as an access type.  In fact, there is no requirement that one access
type have the same representation as another access type.  There are, in
fact, compilers that take advantage of this.  I believe that GNAT, for
example, stores access-to-unconstrained-arrray differently from
access-to-integer.

However, there are some conversions operations back and forth between
Address and any given access type.  See RM9X-13.7.1;5.0.  These aren't
completely portable, either, but they are likely to be in the "simple"
cases.

- Bob
-- 
Bob Duff                                bobduff@inmet.com
Oak Tree Software, Inc.
Ada 9X Mapping/Revision Team (Intermetrics, Inc.)