Re: Equality operator overloading in ADA 83

[bobduff@world.std.com (Robert A Duff)]

In article <dewar.861864029@merv>, Robert Dewar <dewar@merv.cs.nyu.edu> wrote:
>Is this right, I do not know of an AI that has been issued that requires
>equality to compose on the Bounded_String type. Bob (Duff) isn't that
>right -- we discussed it, but made no final decision as I remember.

There is an AI, and I posted it in another note.  The ARG made a "final"
decision, but WG9 has not yet voted on it.

My memory is that we discussed it at the Vermont meeting last Fall (I
believe you were there, since you hosted the meeting ;-) ) and the
entire ARG agreed unanimously that "=" should compose properly for all
predefined types except System.Address.  For System.Address, all but one
ARG member agreed that "=" should compose -- I was the "one", and I
argued that Address semantics are by their nature implementation
dependent, so we shouldn't say anything about it.  I was outvoted on
that point.

So, yes, you ought to change Bounded_String to be tagged, or else use
some special hack.  Unless of course you think WG9 will disapprove the
AI -- I doubt it.  I also remember you saying that such special hacks
are easy to implement in GNAT, so you could save one word per
Bounded_String, if you like.

- Bob