Re: point by point advantages of Ada

["Randy Brukardt" <randy@rrsoftware.com>]

Warren W. Gay VE3WWG wrote in message <3E1B4C4C.7050205@cogeco.ca>...
>Randy Brukardt wrote:

>I thought that this might work:
>
>    declare
>       V : T'Class := ...
>    begin
>       ...
>       V := Some_Other_Func;  - Dispatching
>    end;
>
>But GNAT (at least) reports that this assignment is "ambiguous"
>and will not compile it. I would have expected that it would
>resolve it at runtime, knowing the current value of V and its
>current tag. Is this consistent with the LRM (IANAL)?

Unfortunately, the LRM has no position on this. This case is not covered
at all by the standard. The ARG has been working (slowly) on an AI to
fix this, and it finally was finished in October and approved at the
recent ARG and WG9 meetings. It's AI-196.
    http://www.ada-auth.org/cgi-bin/cvsweb.cgi/AIs/AI-00196.TXT

The solution is essentially to add a paragraph saying that your example
works as you expect. Now, of course, you'll have to wait for Ada
compilers to conform to this ruling. (Which will be helped when an ACATS
test gets added for it.)

               Randy.