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From: Eric Clayberg <clayberg@parcplace.com>
Subject: Re: Static vs. Dynamic typing again (was Re: OO, C++, and something much better!)
Date: 1997/01/23
Date: 1997-01-23T00:00:00+00:00	[thread overview]
Message-ID: <32E7E08A.3079@parcplace.com> (raw)
In-Reply-To: 32E7BD57.2558@calfp.com


Richie Bielak wrote:
> What also wanted to say in my previous post is that static typing
> proves that there is no call in the program that will cause
> the "message not understood" error.

So a static type check can prove that a message wont be sent to an
object whose memory has been freed up prematurely, huh? I don't think
so. A static type check would certainly catch *some* "message not
understood" problems (in particular, those that corresponded to actual
type errors), but by no means all or even most of them. Most "message
not understood" errors are caused by messages being sent to nil (e.g.,
an uninitialized variable or a prematurely freed variable). Furthermore,
the static type checker would not be able to detect errors that were
caused by dynamic message creation and dispatch (e.g., the message
selector is constructed dynamically based on runtime data).
 
> Is the chance of this kind of error "absurdly low"?

For "message not understood" errors that correspond to actual type
errors, yes.

Static type checkers have been developed for Smalltalk (e.g., the
StrongTalk system). They have not been commercially successful so far.
Although they work fine, they are attempting to solve a problem that in
practice isn't really a problem. Smalltalk has been around for a long
time. Techniques for adding static type checking to it have been
available for a long time. If static typing had ever become an important
issue for the Smalltalk community, the Smalltalk vendors (IBM included)
would have provided that capability. It hasn't, so they haven't.

-Eric




  reply	other threads:[~1997-01-23  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
1997-01-28  0:00                             ` David Hanley
     [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                         ` 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                             ` 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
1997-01-23  0:00                             ` Mark Woodruff
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                           ` Robb Nebbe
1997-01-23  0:00                             ` David Hanley
1997-01-25  0:00                             ` Eric Clayberg
1997-01-23  0:00                           ` Matt Kennel
1997-01-25  0:00                             ` Eric Clayberg
1997-01-27  0:00                             ` Jon S Anthony
1997-01-24  0:00                           ` Fergus Henderson
1997-01-24  0:00                             ` Alan Lovejoy
1997-01-26  0:00                             ` Fergus Henderson
1997-01-28  0:00                             ` Alan Knight
1997-01-29  0:00                               ` Nick Leaton
     [not found]                             ` <32E9BAAC. <5ce8t3$6gv@mulga.cs.mu.OZ.AU>
1997-01-28  0:00                               ` Alan Lovejoy
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                         ` Ed Shirk
1997-01-27  0:00                         ` Rolf Breuning
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                     ` 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                             ` Richard Kenner
1997-01-30  0:00                               ` Nick Leaton
1997-01-30  0:00                             ` Robert Dewar
1997-01-27  0:00                     ` Bob Jarvis
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                         ` Matthew Heaney
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                         ` Eric Clayberg
1997-01-28  0:00                     ` Robert I. Eachus
1997-02-08  0:00                   ` Robin Rosenberg
1997-01-27  0:00                 ` Jon S Anthony
1997-01-27  0:00                 ` Eric Clayberg
1997-01-29  0:00                   ` Joachim Durchholz
1997-01-29  0:00                   ` Fergus Henderson
1997-01-27  0:00                 ` David Hanley
1997-01-29  0:00                   ` Joachim Durchholz
1997-01-29  0:00                     ` Dennis Smith
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
1997-01-28  0:00                 ` Luther Hampton
1997-01-28  0:00                 ` David Hanley
1997-01-29  0:00                 ` David Hanley
1997-01-29  0:00                 ` Eric Clayberg
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                 ` Alan Lovejoy
1997-01-28  0:00                 ` Jon S Anthony
1997-01-29  0:00                   ` Robert A Duff
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               ` Dave Gibson
1997-01-28  0:00                 ` Robert A Duff
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
1997-01-21  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                 ` Don Harrison
1997-01-22  0:00                   ` John Kuszewski
1997-01-23  0:00                     ` Don Harrison
1997-01-23  0:00                       ` Tansel Ersavas
1997-01-23  0:00                       ` Travis Griggs
1997-01-24  0:00                     ` Fergus Henderson
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$7df2ad80@wkst01.milagro.austin.tx.us>
1997-01-25  0:00                         ` Nathan M. Urban
1997-01-28  0:00                           ` David L. Shang
1997-01-28  0:00                             ` Nathan M. Urban
1997-01-29  0:00                               ` David L. Shang
1997-01-29  0:00                               ` Russ McClelland
1997-01-28  0:00                             ` Luther Hampton
1997-01-29  0:00                               ` Marc De Scheemaecker
     [not found]                             ` <5d0efr$meb@news.xmission.com>
1997-02-09  0:00                               ` daniel damian burden
1997-01-27  0:00                     ` David L. Shang
1997-01-27  0:00                     ` Robert I. Eachus
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                       ` Eric Clayberg
1997-01-26  0:00                         ` Robert Dewar
1997-01-26  0:00                         ` Robert Dewar
1997-01-25  0:00                     ` Robert Dewar
1997-01-26  0:00                       ` William Clodius
1997-01-27  0:00                   ` Robert C. Martin
1997-01-29  0:00                     ` Robert Dewar
1997-01-29  0:00                       ` Robert A Duff
1997-01-21  0:00             ` Matthew S. Whiting
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
1997-01-24  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
1997-01-27  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               ` Norman H. Cohen
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
1997-01-24  0:00                 ` traymond
1997-01-27  0:00                   ` Norman H. Cohen
1997-01-28  0:00                     ` traymond
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               ` 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                     ` Eric Clayberg [this message]
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
1997-01-23  0:00                     ` Rolf Breuning
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! 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       ` Norman H. Cohen
1997-01-28  0:00       ` Russ McClelland
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! Eric Clayberg
1997-01-25  0:00 ` Tansel Ersavas
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           ` William Clodius
1997-02-19  0:00             ` Mike Klein
1997-02-19  0:00           ` richard
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   ` 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! Alan Lovejoy
1997-02-17  0:00   ` Jon S Anthony
1997-02-18  0:00   ` Bernard Badger
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   ` 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
1997-02-25  0:00     ` Richard A. O'Keefe
1997-02-22  0:00   ` Jon S Anthony
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
1997-02-27  0:00     ` Clayton Weaver
1997-02-25  0:00   ` Jon S Anthony
1997-02-25  0:00   ` Jon S Anthony
1997-02-26  0:00   ` Mike Klein
1997-02-25  0:00 ` Jon S Anthony
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