From: magnus@lglsun.epfl.ch (Magnus Kempe)
Subject: Re: Ichibah [sic] flames, and flames out over, Ada 9X
Date: 11 Mar 93 08:33:47 GMT
Date: 1993-03-11T08:33:47+00:00 [thread overview]
Message-ID: <1993Mar11.090445@lglsun.epfl.ch> (raw)
In-Reply-To: 1993Mar10.201515.6295@evb.com
In article <1993Mar10.201515.6295@evb.com>, jgg@evb.com (John Goodsen) writes:
: If you don't make it easy for someone on the language search to see
: that Ada supports the concept of "class", then the acceptance of the
: language for OO development will not meet it's true potential.
In Ada 9X, you will be able to declare e.g. class-wide objects and
access types, such as:
type Stack_Ref is
access Stack'class;
A : Stack'class;
Is it easy enough to see that Ada 9X has "class" ?
: If the solution is to change the syntax from "tagged type" to
: "class" and leave it at that, then it doesn't sound like too
: much of a problem...
Contrary to OOP languages where objects per se are polymorphic,
Ada objects are monomorphic since Ada has by-value semantics.
Ada 9X programmers will _also_ be able to manage by-reference
semantics to have polymorphic references to objects, which is
what other OOP languages really provide. Generally, a class
declaration in an OOPL implies that instances may belong to
the class itself or to a subclass, and that they are polymorphic;
in consequence, OOPLs rarely perform any significant amount of
strong, static type checking.
You don't want to throw away Ada's strong type system and static
checking, do you?
Anyway, I doubt that the adoption of Ada 9X will rest on the ability
of C++ programmers to grasp that "tagged" is somehow an equivalent of
their "class". I don't think they will, since most C++ programmers
that I know enjoy C++ "because it's compatible with C". Ada is
incompatible with C-oriented minds. And that's a Good Thing.
If you want to learn of the many problems with C++, go read
"C++?? A Critique of C++", Ian Joyner (e-mail: ian@syacus.acus.oz.au)
"A Critique of the Inheritance Principle of C++", Markku Sakkinen,
in Computing Systems, Vol. 5, No. 1, Winter 1992
"The Darker Side of C++ Revisited", Markku Sakkinen,
in Structured Programming (1992) 13: pp. 155-177.
(Warning: Referenceless flames and other hate-mail ignored on principle :-)
--
Magnus Kempe "No nation was ever drunk when wine was cheap."
magnus@lglsun.epfl.ch -- Thomas Jefferson
next prev parent reply other threads:[~1993-03-11 8:33 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
1993-03-10 20:15 Ichibah flames, and flames out over, Ada 9X John Goodsen
1993-03-10 22:41 ` David Emery
1993-03-12 16:01 ` Tom Pole
1993-03-12 22:59 ` Charles H. Sampson
1993-03-16 17:35 ` Classes versus tagged types was " Tom Pole
1993-03-18 16:28 ` In favor of tagged types (was Classes versus tagged types was Ichibah flames, and flames out over, Ada 9X) Stephane Barbey
1993-03-19 18:13 ` Larry M. Jordan
1993-03-13 3:11 ` Ichibah flames, and flames out over, Ada 9X Keith Thompson @pulsar
1993-03-14 15:03 ` Fergus James HENDERSON
1993-03-15 23:19 ` Harry Koehnemann
1993-03-16 2:50 ` Michael Feldman
1993-03-17 18:18 ` Robert Firth
1993-03-12 22:02 ` Anthony Howell
1993-03-11 8:33 ` Magnus Kempe [this message]
-- strict thread matches above, loose matches on Subject: below --
1993-02-21 16:28 Ichibah [sic] " cis.ohio-state.edu!pacific.mps.ohio-state.edu!linac!uwm.edu!wupost!howlan
1993-02-20 2:34 Bob Kitzberger
1993-02-19 12:43 M. Scot t Buck
1993-02-19 10:20 enterpoop.mit.edu!linus!think.com!rpi!ghost.dsi.unimi.it!univ-lyon1.fr!sc
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