Re: Merits of re-dispatching

[brangdon@cix.co.uk (Dave Harris)]

dmitry@elros.cbb-automation.de (Dmitry A. Kazakov) wrote (abridged):
> > This should produce B.Foo B.Foo A.Foo A.Foo.
> 
> With my correction it will produce:
> 
> B.Foo B.Foo B.Foo A.Foo.

Right. So you see that Ada is different from C++, and your description of 
C++ in Ada terms gives the wrong results. You said earlier that:

    That is one of several possible interpretation of what happens
    in C++ using Ada terms.

but the other interpretation you offered doesn't correspond to how C++ 
behaves.

That was my only point, really. 


> Why on earth a call to Foo from B.Finalize should dispatch? The type
> is known, so there is only one version of Foo to be called.

Let's not muddle the issue with compiler optimisations. A C++ compiler is 
allowed to replace dynamic dispatch with static if it can deduce the 
dynamic type of the object at compile-time. Constructors are not a special 
case (although the deduction is unusually simple for them). All of this is 
under the "as if" rule. C++ must behave as if it dynamically dispatched in 
constructors.

  Dave Harris, Nottingham, UK | "Weave a circle round him thrice,
      brangdon@cix.co.uk      |   And close your eyes with holy dread,
                              |  For he on honey dew hath fed
 http://www.bhresearch.co.uk/ |   And drunk the milk of Paradise."