Re: Ada2005

[Ray Blaak <blaak@telus.net>]

"Mark Lundquist" <no.spam@getalife.com> writes:
> "Ray Blaak" <blaak@telus.net> wrote in message
> Doesn't it make a mishmash of the name resolution rules?  Consider
> 
>         type Note is private;
> 
>         function Pitch (Subject : Note) return Note_Properties.Pitch;
>         function Length (Subject : Note) return Note_Properties.Length;
> 
>     private
> 
>         type Note is record
>             Pitch : Note_Properties.Pitch;
>             Length : Note_Properties.Lenght;
>         end record;
> 
> In the body of the package, how do you resolve the name "X.Pitch" for an X
> of type Note?

First off, I should say that I am not strongly advocating this change to be
made to Ada, even though I would prefer if I could do this kind of thing.

This is really only a thought experiment.

At any rate, I would resolve X.Pitch by saying that record fields "win" if the
field is accessible. The Pitch method would win only if:

a) Note is accessible as a tagged type at the point of call
b) Pitch is not accessible as a field at the point of call
c) Pitch is accessible as a primitive operation at the point of call

If both the field and method are accessible and are ambiguous, one could just
choose the field, since that is existing Ada semantics. A warning about the
ambiguity could possibly also be reported, so as to inform the user.

For regular record types (or any other type, for that matter), this syntactic
transformation need not apply.

I only prefer it for OO programming, where I tend to think in terms of asking
an object to do something, as opposed to asking something to be done to an
object, if you know what I mean.

-- 
Cheers,                                        The Rhythm is around me,
                                               The Rhythm has control.
Ray Blaak                                      The Rhythm is inside me,
blaak@telus.net                                The Rhythm has my soul.