From: Dave Gibson <dgibson@cis.ohio-state.edu>
Cc: dgibson@cis.ohio-state.edu
Subject: Multiple Type Interfaces
Date: 1997/01/28
Date: 1997-01-28T00:00:00+00:00 [thread overview]
Message-ID: <32EE352A.167EB0E7@cis.ohio-state.edu> (raw)
In-Reply-To: 6PE5zLpF3RB@herold.franken.de
From another very long thread:
> > There are subtle differences between 'type', 'interface', and 'class'
> > and the terms get used somewhat interchangebly around here.
They are used interchangebly by some and with completely different meanings
by others. In general, 'type' and 'interface' are not used with precisely
defined meanings outside of the context of specific programming languages.
> I think these differences are mostly artificial. They have been introduced
> to capture subtle differences in the way languages implement various
> concepts.
>
> To my understanding, a class is a piece of program code, and an interface
> (or type) is everything that one must know to use that class. So an
> interface is a set of routine signatures and maybe class invariants,
> routine preconditions and routine postconditions.
Here's another view. A type is a name for a mathematical set of values or a name
for a programming language- and environment-specific set of values. For formal
reasoning about program behavior, it is convenient to model `program types' by
purely `mathematical' types. An interface describes the externally-observable
elements of a component which consist of a structural signature and behavior
(ideally explicitly specified). In general, an interface may include any
number of types. A class is the common name for a programming langauge
component in some OO langauges where it defines a programming language type, an
interface, and may include other elements not part of the interface.
I am curious about "inheritance-like" relationships between components which export
multiple types. Languages like Ada, Modula 2, ML, and others, support component
interfaces that may include zero or more program types. It seems like it should
be possible to define behavioral substitutability relationships between such
components. For example, if component A "includes" all of component B's interface,
then component A should be behaviorally substitutable for component B in some
informal sense. This seems reasonable to me independently of whether component B's
interface includes zero, one, or more types.
When Ada83 evolved into Ada95, the concept of multiple type components (packages)
survived, but was excluded when it came to OO-style (extendable) tagged types.
Clearly packages exporting multiple tagged types would not fit the common OO model
in which the concepts of "class" and program type are tightly coupled. Nevertheless,
why not define a language so components can export multiple types which may be
extended in other related "derived" components? Was this ever considered? Was it
just not considered the OO way by Ada95 language designers? Perhaps it would
be extremely complicated to implement with little perceived gain. I'd appreciate any
comments on this topic.
Dave
--
dgibson@cis.ohio-state.edu
next prev parent reply other threads:[~1997-01-28 0:00 UTC|newest]
Thread overview: 379+ messages / expand[flat|nested] mbox.gz Atom feed top
1997-01-16 0:00 OO, C++, and something much better! Jon S Anthony
1997-01-17 0:00 ` Don Harrison
1997-01-16 0:00 ` Matthew Heaney
1997-01-17 0:00 ` Alan Lovejoy
1997-01-17 0:00 ` Norman H. Cohen
1997-01-17 0:00 ` Alan Lovejoy
1997-01-18 0:00 ` Fergus Henderson
1997-01-17 0:00 ` Alan Lovejoy
1997-01-20 0:00 ` Damon Feldman
1997-01-19 0:00 ` Alan Lovejoy
1997-01-20 0:00 ` Graham Hughes
1997-01-21 0:00 ` Alan Lovejoy
1997-01-21 0:00 ` Matt Kennel
1997-01-21 0:00 ` Marc Robertson
1997-01-24 0:00 ` Mark Windholtz
1997-01-27 0:00 ` David Hanley
1997-01-28 0:00 ` Eric Clayberg
[not found] ` <32EE2FEE.62FE@p <32EE8415.2F5B@netright.com>
1997-01-28 0:00 ` Eric Clayberg
1997-01-29 0:00 ` David Hanley
1997-01-29 0:00 ` Eric Clayberg
1997-01-28 0:00 ` David Hanley
1997-01-28 0:00 ` Alan Lovejoy
1997-01-29 0:00 ` Matt Kennel
1997-01-30 0:00 ` Alan Lovejoy
1997-01-30 0:00 ` David L. Shang
1997-01-30 0:00 ` Black box or white box (Re: OO, C++, and something much better!) David L. Shang
1997-01-29 0:00 ` OO, C++, and something much better! Jun Nolasco
1997-01-22 0:00 ` Fergus Henderson
1997-01-22 0:00 ` Fergus Henderson
1997-01-22 0:00 ` Eric Clayberg
1997-01-22 0:00 ` Graham Hughes
1997-01-23 0:00 ` Mark Woodruff
1997-01-23 0:00 ` Eric Clayberg
1997-01-23 0:00 ` Claus Reinke
1997-01-25 0:00 ` Eric Clayberg
1997-01-25 0:00 ` Fergus Henderson
1997-01-25 0:00 ` Lawrence G. Mayka
1997-01-28 0:00 ` Claus Reinke
1997-01-24 0:00 ` Don Harrison
1997-01-24 0:00 ` Eric Clayberg
1997-01-28 0:00 ` Don Harrison
1997-01-24 0:00 ` Richard A. O'Keefe
[not found] ` <E4voIF.86o@world.std.com>
1997-02-12 0:00 ` Ulf Schuenemann
1997-01-23 0:00 ` Matt Kennel
1997-01-25 0:00 ` Eric Clayberg
1997-01-27 0:00 ` Jon S Anthony
1997-01-23 0:00 ` Robb Nebbe
1997-01-23 0:00 ` David Hanley
1997-01-25 0:00 ` Eric Clayberg
1997-01-24 0:00 ` Fergus Henderson
1997-01-24 0:00 ` Alan Lovejoy
1997-01-26 0:00 ` Fergus Henderson
[not found] ` <32E9BAAC. <5ce8t3$6gv@mulga.cs.mu.OZ.AU>
1997-01-28 0:00 ` Alan Lovejoy
1997-01-28 0:00 ` Alan Knight
1997-01-29 0:00 ` Nick Leaton
1997-01-29 0:00 ` Fergus Henderson
1997-01-30 0:00 ` Alan Lovejoy
1997-01-24 0:00 ` Richard A. O'Keefe
1997-01-25 0:00 ` Joachim Durchholz
1997-01-27 0:00 ` Rolf Breuning
1997-01-27 0:00 ` Ed Shirk
1997-01-20 0:00 ` Bill Gooch
1997-01-20 0:00 ` David Hanley
1997-01-21 0:00 ` Alan Lovejoy
1997-01-22 0:00 ` Fergus Henderson
1997-01-22 0:00 ` Alan Lovejoy
1997-01-23 0:00 ` Bob Jarvis
1997-01-22 0:00 ` Damon Feldman
1997-01-29 0:00 ` Joachim Durchholz
1997-01-25 0:00 ` Jon S Anthony
1997-01-25 0:00 ` Eric Clayberg
1997-01-26 0:00 ` Robert Dewar
1997-01-27 0:00 ` Bob Jarvis
1997-01-27 0:00 ` Robert Dewar
1997-01-27 0:00 ` Eric Clayberg
1997-01-27 0:00 ` Matthew Heaney
1997-01-27 0:00 ` Robert A Duff
1997-01-29 0:00 ` Robert Dewar
1997-01-27 0:00 ` Eric Clayberg
1997-01-29 0:00 ` Robert Dewar
1997-01-29 0:00 ` Robert A Duff
1997-01-29 0:00 ` Eric Clayberg
1997-01-27 0:00 ` Samuel S. Shuster
1997-01-27 0:00 ` Richard Kenner
1997-01-29 0:00 ` Robert Dewar
1997-01-30 0:00 ` Eirik Mangseth
1997-01-28 0:00 ` Jun Nolasco
1997-01-29 0:00 ` Robert Dewar
1997-01-29 0:00 ` Richard Kenner
1997-01-29 0:00 ` David Hanley
1997-01-29 0:00 ` Richard Kenner
1997-01-30 0:00 ` Nick Leaton
1997-01-30 0:00 ` Robert Dewar
1997-01-30 0:00 ` Richard Kenner
1997-01-30 0:00 ` Nick Leaton
1997-01-28 0:00 ` Robert I. Eachus
1997-02-08 0:00 ` Robin Rosenberg
1997-01-27 0:00 ` David Hanley
1997-01-29 0:00 ` Joachim Durchholz
1997-01-29 0:00 ` Dennis Smith
1997-01-27 0:00 ` Eric Clayberg
1997-01-29 0:00 ` Fergus Henderson
1997-01-29 0:00 ` Joachim Durchholz
1997-01-27 0:00 ` Jon S Anthony
1997-01-28 0:00 ` David Hanley
1997-01-28 0:00 ` Luther Hampton
1997-01-28 0:00 ` Eric Clayberg
1997-01-28 0:00 ` Matt Kennel
1997-01-28 0:00 ` David Hanley
1997-01-28 0:00 ` Jacqueline U. Robertson
1997-01-29 0:00 ` David Hanley
1997-01-29 0:00 ` Fergus Henderson
1997-01-30 0:00 ` Robert C. Martin
[not found] ` <5cr068$gpa@uni.library.ucla.edu>
1997-06-27 0:00 ` David Shang
1997-06-28 0:00 ` Mike Stark
1997-06-28 0:00 ` Ronald E Jeffries
1997-06-29 0:00 ` Mike Anderson
1997-06-29 0:00 ` Robert Dewar
1997-06-30 0:00 ` Kohler Markus
1997-01-29 0:00 ` Joachim Durchholz
1997-01-28 0:00 ` Robert I. Eachus
1997-01-29 0:00 ` Eric Clayberg
1997-01-29 0:00 ` David Hanley
1997-01-29 0:00 ` Jon S Anthony
1997-01-29 0:00 ` Eric Clayberg
1997-01-29 0:00 ` Rolf Breuning
1997-01-20 0:00 ` Fergus Henderson
1997-01-19 0:00 ` Alan Lovejoy
1997-01-25 0:00 ` Robert Dewar
1997-01-27 0:00 ` Bob Jarvis
1997-01-27 0:00 ` Robert Dewar
1997-01-28 0:00 ` Alan Lovejoy
1997-01-25 0:00 ` Robert Dewar
1997-01-26 0:00 ` James O'Connor
1997-01-26 0:00 ` Robert Dewar
1997-01-26 0:00 ` George Wolke
1997-01-27 0:00 ` Jerry van Dijk
1997-01-28 0:00 ` Robert A Duff
1997-01-28 0:00 ` Jerry van Dijk
1997-01-29 0:00 ` Stanley R. Allen
1997-01-30 0:00 ` Robert A Duff
1997-01-28 0:00 ` Jon S Anthony
1997-01-29 0:00 ` Robert A Duff
1997-01-28 0:00 ` Alan Lovejoy
1997-01-19 0:00 ` Soren Skogstad Nielsen
1997-01-20 0:00 ` Joachim Durchholz
1997-01-26 0:00 ` Joachim Durchholz
1997-01-29 0:00 ` Multiple Type Interfaces Jon S Anthony
1997-01-28 0:00 ` Norman H. Cohen
1997-01-28 0:00 ` david scott gibson
1997-01-28 0:00 ` Matthew Heaney
1997-01-29 0:00 ` david scott gibson
1997-01-29 0:00 ` Robert A Duff
1997-01-29 0:00 ` david scott gibson
1997-01-28 0:00 ` Dave Gibson [this message]
1997-01-28 0:00 ` Robert A Duff
1997-01-21 0:00 ` OO, C++, and something much better! Matthew S. Whiting
1997-01-22 0:00 ` Fergus Henderson
1997-01-22 0:00 ` Alan Lovejoy
1997-01-22 0:00 ` Eric Clayberg
1997-01-23 0:00 ` Don Harrison
1997-01-27 0:00 ` John Woods
1997-01-28 0:00 ` Alan Lovejoy
1997-01-23 0:00 ` Combining dynamic and static typing Don Harrison
1997-01-24 0:00 ` Erik M. Buck
[not found] ` <01bc0b21$6a8293e0$7df2ad80@wkst01.milagro.austin.tx.us>
1997-01-25 0:00 ` Nathan M. Urban
1997-01-28 0:00 ` David L. Shang
1997-01-28 0:00 ` Luther Hampton
1997-01-29 0:00 ` Marc De Scheemaecker
1997-01-28 0:00 ` Nathan M. Urban
1997-01-29 0:00 ` Russ McClelland
1997-01-29 0:00 ` David L. Shang
[not found] ` <5d0efr$meb@news.xmission.com>
1997-02-09 0:00 ` daniel damian burden
1997-01-27 0:00 ` Robert I. Eachus
1997-01-27 0:00 ` David L. Shang
1997-01-28 0:00 ` Robert C. Martin
1997-01-29 0:00 ` David L. Shang
1997-01-24 0:00 ` OO, C++, and something much better! Andy Bower
1997-01-25 0:00 ` Robert Dewar
1997-01-26 0:00 ` William Clodius
1997-01-25 0:00 ` Robert Dewar
1997-01-26 0:00 ` Eric Clayberg
1997-01-26 0:00 ` Robert Dewar
1997-01-26 0:00 ` Robert Dewar
1997-01-27 0:00 ` Robert C. Martin
1997-01-29 0:00 ` Robert Dewar
1997-01-29 0:00 ` Robert A Duff
1997-01-22 0:00 ` Don Harrison
1997-01-22 0:00 ` John Kuszewski
1997-01-23 0:00 ` Don Harrison
1997-01-23 0:00 ` Travis Griggs
1997-01-23 0:00 ` Tansel Ersavas
1997-01-24 0:00 ` Fergus Henderson
1997-01-21 0:00 ` Matthew S. Whiting
1997-01-24 0:00 ` Tansel Ersavas
1997-01-25 0:00 ` Damon Feldman
1997-01-26 0:00 ` Felix Beer
1997-01-28 0:00 ` Robert C. Martin
1997-01-28 0:00 ` Matt Kennel
1997-01-29 0:00 ` Del Archer
1997-01-24 0:00 ` Tansel Ersavas
1997-01-25 0:00 ` Fergus Henderson
1997-01-25 0:00 ` Robert A Duff
1997-01-26 0:00 ` Robert Dewar
1997-01-26 0:00 ` James O'Connor
1997-01-26 0:00 ` TanselErsavas
1997-01-26 0:00 ` Robert Dewar
1997-01-27 0:00 ` Eric Clayberg
1997-01-28 0:00 ` Antoine Trux
1997-01-29 0:00 ` Robert Dewar
1997-01-26 0:00 ` Bob Haugen
1997-01-26 0:00 ` Larry J. Elmore
1997-01-26 0:00 ` Eric Clayberg
1997-01-26 0:00 ` Robert Dewar
1997-01-26 0:00 ` TanselErsavas
1997-01-27 0:00 ` Samuel S. Shuster
1997-01-27 0:00 ` David Hanley
1997-01-24 0:00 ` Tansel Ersavas
1997-01-27 0:00 ` David Hanley
1997-01-28 0:00 ` OO, C++, and more and more useless arguments! Robert C. Martin
1997-01-28 0:00 ` OO, C++, and something much better! Al Christians
1997-01-28 0:00 ` Alan Lovejoy
1997-01-29 0:00 ` Alan Lovejoy
1997-02-21 0:00 ` Chris Bitmead
1997-02-21 0:00 ` Eric W. Nikitin
1997-02-21 0:00 ` Brian Rogoff
1997-02-24 0:00 ` Jon S Anthony
1997-02-24 0:00 ` Brian Rogoff
1997-02-25 0:00 ` Eric W. Nikitin
1997-01-21 0:00 ` Norman H. Cohen
1997-01-22 0:00 ` Eric Clayberg
1997-01-23 0:00 ` Static vs. Dynamic typing again (was Re: OO, C++, and something much better!) Richie Bielak
1997-01-23 0:00 ` Bill Gooch
1997-01-23 0:00 ` Eric Clayberg
1997-01-23 0:00 ` Richie Bielak
1997-01-24 0:00 ` Eirik Mangseth
[not found] ` <32E85588.1978@parcplace.com>
1997-01-26 0:00 ` Paul Perkins
1997-01-26 0:00 ` Robert A Duff
1997-01-29 0:00 ` John Gale
1997-01-30 0:00 ` Robert A Duff
1997-01-28 0:00 ` Damon Feldman
1997-01-28 0:00 ` Eric Clayberg
1997-01-23 0:00 ` Richie Bielak
1997-01-23 0:00 ` Rolf Breuning
1997-01-23 0:00 ` Eric Clayberg
1997-01-24 0:00 ` Robb Nebbe
1997-01-25 0:00 ` OO, C++, and something much better! David N. Smith
1997-01-24 0:00 ` Static vs. Dynamic typing again (was Re: OO, C++, and something much better!) Richie Bielak
1997-01-24 0:00 ` Bob Jarvis
1997-01-24 0:00 ` Richie Bielak
1997-01-27 0:00 ` Eric W. Nikitin
1997-01-25 0:00 ` Robert A Duff
1997-01-30 0:00 ` Damon Feldman
1997-01-30 0:00 ` Robert A Duff
1997-01-30 0:00 ` Fergus Henderson
1997-01-30 0:00 ` Defintion, again, was Re: Static vs. Dynamic typing again David L. Shang
1997-02-09 0:00 ` Static vs. Dynamic typing again (was Re: OO, C++, and something much better!) Piercarlo Grandi
1997-02-10 0:00 ` Matt Kennel
1997-02-14 0:00 ` Piercarlo Grandi
1997-02-15 0:00 ` Pieter Schoenmakers
1997-02-16 0:00 ` Piercarlo Grandi
1997-01-27 0:00 ` Jun Nolasco
1997-01-28 0:00 ` Mark Windholtz
1997-01-28 0:00 ` Richie Bielak
1997-01-28 0:00 ` Alan Knight
1997-02-08 0:00 ` Static vs. Dynamic typing again (was Re: OO, C++, and something mu Joachim Durchholz
1997-01-23 0:00 ` OO, C++, and something much better! Norman H. Cohen
1997-01-24 0:00 ` traymond
1997-01-27 0:00 ` Norman H. Cohen
1997-01-28 0:00 ` traymond
1997-01-24 0:00 ` Eric Clayberg
1997-01-27 0:00 ` Norman H. Cohen
1997-01-28 0:00 ` Tim Ottinger
1997-01-29 0:00 ` Ted Dennison
1997-01-25 0:00 ` Tansel Ersavas
1997-01-27 0:00 ` Norman H. Cohen
1997-01-27 0:00 ` Brian Rogoff
1997-01-28 0:00 ` Reflection in Ada (was: Re: OO, C++, and something much better!) Norman H. Cohen
1997-01-29 0:00 ` Eric W. Nikitin
1997-01-30 0:00 ` OO, C++, and something much better! Tim Ottinger
1997-01-23 0:00 ` James O'Connor
1997-01-29 0:00 ` Stanley R. Allen
1997-01-30 0:00 ` Robert A Duff
1997-01-27 0:00 ` Jon S Anthony
1997-01-19 0:00 ` Keith Thompson
1997-01-22 0:00 ` Don Harrison
1997-01-23 0:00 ` Norman H. Cohen
1997-01-24 0:00 ` Don Harrison
1997-01-27 0:00 ` Norman H. Cohen
1997-01-29 0:00 ` "(Sub)type" -safety Don Harrison
1997-01-29 0:00 ` Jon S Anthony
1997-01-30 0:00 ` Don Harrison
1997-01-23 0:00 ` OO, C++, and something much better! Robert I. Eachus
1997-01-20 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-01-24 0:00 ` Jon S Anthony
1997-01-26 0:00 ` Eric Clayberg
1997-01-27 0:00 ` Jon S Anthony
1997-01-27 0:00 ` Jon S Anthony
1997-01-27 0:00 ` Jon S Anthony
1997-01-28 0:00 ` Jon S Anthony
1997-01-29 0:00 ` Stephen J Bevan
1997-01-21 0:00 ` Joachim Durchholz
1997-01-22 0:00 ` Richard A. O'Keefe
1997-01-27 0:00 ` Robert Dewar
1997-01-27 0:00 ` Robert A Duff
1997-01-29 0:00 ` Robert Dewar
1997-01-27 0:00 ` Robert A Duff
1997-01-27 0:00 ` Bob Jarvis
1997-01-28 0:00 ` Travis Griggs
1997-01-28 0:00 ` Russ McClelland
1997-01-28 0:00 ` Norman H. Cohen
1997-01-27 0:00 ` John Woods
1997-01-22 0:00 ` Eric Clayberg
1997-01-23 0:00 ` Joachim Durchholz
1997-01-24 0:00 ` Joachim Durchholz
1997-01-29 0:00 ` Multiple Type Interfaces Joachim Durchholz
1997-01-25 0:00 ` OO, C++, and something much better! Tansel Ersavas
1997-01-25 0:00 ` Eric Clayberg
1997-01-25 0:00 ` James O'Connor
1997-01-26 0:00 ` Lawrence G. Mayka
1997-01-26 0:00 ` James O'Connor
1997-01-27 0:00 ` Norman H. Cohen
1997-02-07 0:00 ` Richard A. O'Keefe
1997-02-07 0:00 ` Alan Lovejoy
1997-02-12 0:00 ` Piercarlo Grandi
1997-02-13 0:00 ` Alan Lovejoy
[not found] ` <yf3ybcsm5ce.fsf@sabi.demon.co.uk>
1997-02-14 0:00 ` Alan Lovejoy
1997-02-16 0:00 ` Piercarlo Grandi
1997-02-16 0:00 ` Alan Lovejoy
1997-02-17 0:00 ` Piercarlo Grandi
1997-02-13 0:00 ` Richard A. O'Keefe
1997-02-13 0:00 ` Alan Lovejoy
1997-02-18 0:00 ` Richard A. O'Keefe
1997-02-19 0:00 ` richard
1997-02-19 0:00 ` William Clodius
1997-02-19 0:00 ` Mike Klein
1997-02-19 0:00 ` Mike Klein
1997-02-15 0:00 ` Jon S Anthony
1997-02-16 0:00 ` Piercarlo Grandi
1997-02-16 0:00 ` Definition of "operator" (was: OO, C++, and something much better!) Alan Lovejoy
1997-02-19 0:00 ` Dave Schaumann
1997-02-19 0:00 ` Anders Pytte
1997-02-16 0:00 ` OO, C++, and something much better! Jon S Anthony
1997-02-18 0:00 ` Richard A. O'Keefe
1997-02-20 0:00 ` Matt Kennel
1997-02-20 0:00 ` Anders Pytte
1997-02-17 0:00 ` Jon S Anthony
1997-02-19 0:00 ` Piercarlo Grandi
1997-02-17 0:00 ` Jon S Anthony
1997-02-19 0:00 ` Piercarlo Grandi
1997-02-19 0:00 ` Mike Klein
1997-02-17 0:00 ` Alan Lovejoy
1997-02-17 0:00 ` Definition of "operator" (was: OO, C++, and something much better!) Alan Lovejoy
1997-02-19 0:00 ` David L. Shang
1997-02-21 0:00 ` Jon S Anthony
1997-02-24 0:00 ` David L. Shang
1997-02-25 0:00 ` Jon S Anthony
1997-02-17 0:00 ` OO, C++, and something much better! Jon S Anthony
1997-02-18 0:00 ` Jon S Anthony
1997-02-19 0:00 ` Piercarlo Grandi
1997-02-19 0:00 ` Piercarlo Grandi
1997-02-18 0:00 ` Bernard Badger
1997-02-18 0:00 ` Definition of "operator" (was: OO, C++, and something much better!) Jon S Anthony
1997-02-21 0:00 ` OO, C++, and something much better! Jon S Anthony
1997-02-24 0:00 ` Piercarlo Grandi
1997-02-22 0:00 ` Jon S Anthony
1997-02-22 0:00 ` Jon S Anthony
1997-02-22 0:00 ` Jon S Anthony
1997-02-22 0:00 ` Jon S Anthony
1997-02-22 0:00 ` Jon S Anthony
1997-02-25 0:00 ` Richard A. O'Keefe
1997-02-23 0:00 ` Definition of "operator" (was: OO, C++, and something much better!) Richard Katz
1997-02-24 0:00 ` David L. Shang
1997-02-25 0:00 ` OO, C++, and something much better! Jon S Anthony
1997-02-25 0:00 ` Jon S Anthony
1997-02-25 0:00 ` Jon S Anthony
1997-02-27 0:00 ` Clayton Weaver
1997-02-26 0:00 ` Mike Klein
1997-02-25 0:00 ` Jon S Anthony
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