Re: Ada OO Mechanism

[Samuel Mize <smize@imagin.net>]

Hyman Rosen <hymie@prolifics.com> wrote:
> So you mean in Ada, I can write a dot(a,b) which will dispatch on
> either a or b?

Yes.  Either can be controlling.  If both are controlling, they both
have to be of the same type (the same class in C++ terms).

[uncompiled example]

  type A_Type is tagged with null record;

  -- All of these dispatch on A if it's a dispatching call

  procedure Operation_1 (A: A_Type; I: Integer);

  procedure Operation_2 (I: Integer; A: A_Type);

  procedure Operation_3 (A: A_Type; B: A_Type'Class);

  -- This dispatches on both parameters, so they have to match
  -- at run-time

  procedure Operation_4 (A: A_Type; B: B_Type);


> Once again, I will ask for an example demonstrating this, where
> something is more complicated to use in C++ generics than in Ada.
> This will make you the fourth person I have asked for this type
> of example, the others being Richard D. Riehle, Samuel Mize, and
> Robert Dewar. None of the others have chosen to post such an
> example.

Not instantly.  I did address this to the best of my ability in
another message, just today.  I'll grant that I don't have a code
example handy, and I'll grant that I was repeating "conventional
wisdom" from the group.

Did you intend that paragraph to sound contentious?  To my ear,
at least, it has rather a "you're all liars, I'm naming names"
sound to it -- I hope that isn't what you meant.

Best,
Sam Mize

-- 
Samuel Mize -- smize@imagin.net (home email) -- Team Ada
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