From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00
	autolearn=unavailable autolearn_force=no version=3.4.4
Path: 
 eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!news.eternal-september.org!feeder.eternal-september.org!aioe.org!.POSTED!not-for-mail
From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Ada wikibook help needed (O-O)
Date: Sun, 23 Apr 2017 12:52:10 +0200
Organization: Aioe.org NNTP Server
Message-ID: <odi10p$ojq$1@gioia.aioe.org>
References: <odhv2v$9vi$1@dont-email.me>
NNTP-Posting-Host: BYuA7L7MRjuLLjcoGHOBxw.user.gioia.aioe.org
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
X-Complaints-To: abuse@aioe.org
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101
 Thunderbird/45.8.0
X-Notice: Filtered by postfilter v. 0.8.2
Xref: news.eternal-september.org comp.lang.ada:46612
Date: 2017-04-23T12:52:10+02:00
List-Id: <comp.lang.ada>

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