Re: Ada wikibook help needed (O-O)

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On 2017-04-23 12:22, G.B. wrote:

> The page goes to some length to explain static dispatching
> vs. dynamic dispatching, but fails to introduce "dispatching"
> first, as a term, or to reference some suitable definition.

It does in the section "Polymorphism, class-wide programming and dynamic 
dispatching". Dispatching is a mechanism of polymorphic call 
implementation for the case of dynamic polymorphism.

> Then,
>
>   "A conversion to the class-wide type makes [components] visible again."
>
> Is "visible" correct?

Why not? The text IMO just explains specific implementation of 
class-wide objects in Ada. That is, the same representation of 
class-wide and specific objects.

> Is it correct to say “static call” at all,

Why not? A statically bound call.

> The idea being that “static call” is not really defined in Ada AFAICT,
> other than to mean a call of a static function in a static expression.
> So, not the same thing as discussing O-O, or static binding,
> or dynamic dispatch.
>
>    "In other OO languages, a method is either dispatching or not.

The first sentence is wrong. A non-dispatching operation is not a 
method. In OO nomenclature that is called "free" operation. So, all 
operations are subdivided into methods and free operations. In Ada 
methods are called primitive operation (in some arguments/result). There 
rest is free operations.

>    In Ada, a routine is either _available_ for dispatching or not. "

The second sentence is meaningless to me. There is no difference between 
Ada and other languages in that respect.

Maybe the writer meant the difference that some languages like C++ are 
inconsistent in the sense that the same name may mean polymorphic 
(dispatching) or non-polymorphic (specific) call depending on the 
context. In Ada it is unambiguous.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de