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From: jgg@evb.com (John Goodsen)
Subject: Re: Ada 9X _has_ "class"
Message-ID: <1993Mar19.213439.2342@evb.com>
Organization: EVB Software Engineering, Inc.
Date: Fri, 19 Mar 1993 21:34:39 GMT
Date: 1993-03-19T21:34:39+00:00
List-Id: <comp.lang.ada>


In <1993Mar18.181325@lglsun.epfl.ch> magnus@lglsun.epfl.ch 
(Magnus Kempe) writes:

>
>For those concerned with market penetration.
>
>Ada 9X _does_ have classes (conceptually and literally):
>
>	type T_Ref is access T'class; -- note: "class"
>
>	procedure P (X : T'class) is  -- note: "class"
>	  Y : T'class := X;           -- note: "class"
>	begin
>	  ...
>	end P;
>

This doesn't cut it.

The 'CLASS attribute is not what you will see in marketing literature.
What you will see in Marketing literature is "tagged types" :-(
Unless these people are smart to insert the term "class-wide types"
which has been the actual language used when discussing tagged
types by the Ada 9X.  Since this has been the language used by
the Ada 9X committe, why not finish the game and change the syntax
from "type T is tagged..." to "class type T is ...".

Then you won't have to dig into code to figure out that CLASS is part
ofthe language, but you can see it directly from marketing literature.


>
>In addition, Ada 9X clearly distinguishes between types that belong
>to classes ("Tag", they're it...) and types that don't.  This is
>particularly important for real-time systems.  Some people might
>want to avoid any possibility of e.g. hidden run-time type-checking
>or dynamic binding.  
>

The "class type" terminology will also solve this problem also, *AND*
provide pre-defined terminology for the (non-technical) marketing
folks to use.  Don't expect the marketing people to become educators
on what a tagged type really is.  Give them direct ammo by changing
the terminology now while it is still (potentially) an option?

>
>The real-time community has contributed many
>requirements to the language (have you seen the protected types?
>the distributed systems annex?).  

Yes.  It's very nice.


>
>Ada is not a toy language.
>

No one in this thread is implying that.  Do you want your "Beta"
format language to go out and compete against the "VHS" world
of OO programming languages?  I for one am willing to learn from
past marketing mistakes and not repeat them.  

I'm still waiting for a serious argument on why "tagged type"
is better than "class type".  This is why Mr. Ichbiah left.
I just read the rationale and don't agree with it.  Possibly
you could post that little blurb on the "class type" proposal
and rationale for not implement it, Tucker, and let people 
following this thread have a peek?


-- 
John Goodsen                EVB Software Engineering, Inc.
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