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From: horstman@mathcs.sjsu.edu (Cay Horstmann)
Newsgroups: comp.lang.c++
Subject: Re: Borland language extension virtual function = [ ... ];
Message-ID: <1991Jun28.022445.12167@mathcs.sjsu.edu>
Date: 28 Jun 91 02:24:45 GMT
References: <1991Jun27.130247.5107@mathcs.sjsu.edu> <1991Jun27.210518.19589@Think.COM>
Organization: San Jose State University - Math/CS Dept.
Lines: 43

In article <1991Jun27.210518.19589@Think.COM> barmar@think.com writes:
>In article <1991Jun27.130247.5107@mathcs.sjsu.edu> horstman@mathcs.sjsu.edu (Cay Horstmann) writes:
[my tedious explanation of a nonstandard scheme in BC++ deleted...]
>
>How do you think new features get added to languages?  Almost all good
>features start out life as someone's private extension.  If the extension
>becomes popular then it turns into a de facto standard, and may later find
>its way into an official standard.
>
>Features that are invented by the standards committee frequently turn out
>to be bad ideas, because they are adopted before there has been much
>experience with them.
>
>C++ itself was once someone's extensions to C.
>
All this is true enough. I guess there are three things that bother me about
this.

(1) Borland is trying very heavily to get the OMG to buy into their scheme.
    Now if anyone is ill-equipped to make any judgment on the side effect
    this would have on the C++ language, it is that body. [Maybe I am over-
    reacting here; I have not actually seen what their OMG proposal encom-
    passes.]
	Anyway, they shouldn't propose a library as a standard to the OMG
    which is based on a non-standard language extension.

(2) As far as I can tell, this particular feature is extraordinarily poorly
    thought out. There almost certainly are better ways of doing this that
    don't require breaking the language. [I might be wrong; maybe the feature
    is much more general and useful than it appeared. Does anyone know?]

(3) There generally are several phases in the design of any language. With
    C++, it seemed to be the feeling of the standards committee that the
    experimental phase is largely over (except, I guess, with templates and
    exception handling, the latter of which they have no business standar-
    dizing on, if you ask me), and to a degree I concur with that feeling.
    [I realize that I have in the past argued the other way around, but that
    was only with features I invented, hence truly great and necessary ones.]

Really, I am hoping that someone who has actually used this feature can set
me straight on its semantics and usefulness.

Cay