Archive-name: smalltalk-faq
Last-modified: 1993/6/1
Version: 3.3


***

	This is a Smalltalk frequently-asked-questions (FAQ) document,
distributed by Craig Latta (latta@xcf.Berkeley.EDU). It is posted
fortnightly to the USENET newsgroups comp.lang.smalltalk and
news.answers.
	It is also available via ftp as
anonymous@xcf:misc/smalltalk/FAQ/FAQ.entire. Finally, it can be
obtained by mail by emailing smalltalk-request@xcf with the subject
line "request for FAQ". The machine xcf.Berkeley.EDU has IP address
128.32.138.1.

	You may do anything you like with this document, except sell
it or modify it (including the news headers and ending signature).

        Please send contributions, suggestions and comments to
smalltalk-request@xcf.Berkeley.EDU.
	Comments and suggestions are greatly appreciated. I realize
that information has a short half-life.


        Thanks,

-C


***

	New items are marked with a '+'. Modified existing items are
marked with a '*'. 


	Contents:

0.0)	[Meta-issues]	
0.1)		How can I browse ftp sites and their data without
			using my own disk space (unless I want to keep
			data), and locate files on ftp sites, given
			pathname fragments?

1.0) 	[Archival]
1.1) 		What free or low-cost Smalltalk implementations are
			there? How can I get GNU Smalltalk?
1.2)		What Smalltalk archives are there?

2.0) 	[Projects]
2.1)		What is Smallmusic?
2.2)+		What is CoolDraw?

3.0) 	[References]
3.1)		Can someone recommend a good introduction to
			Model-View-Controller concepts?
3.2)		Is there a Smalltalk bibliography?
3.3)		What are the "blue book", "purple book", etc?
3.4)		Who are some employers of Smalltalk programmers?
3.5)		What is the Smalltalk Report?
3.6)  		Is there a GNU Smalltalk tutorial?
3.7)+		What's a summary of multiple inheritance in Smalltalk?

4.0)	[Programming issues]
4.1)		What are some "classic Smalltalk bugs", both in the
			system and programmer domains?

5.0)	["Vendor"-specific issues]
5.1)		How compatible is GNU Smalltalk with Smalltalk-80 (or
			Smalltalk/V)?

---

0.0) [Meta-issues]	

---

0.1)		How can I browse ftp sites and their data without
			using my own disk space (unless I want to keep
			data), and locate files on ftp sites, given
			pathname fragments?

Answer:

	This question might seem tangential at first (and I suppose it
is). But it is vitally important, as resources such as papers,
documentation, code and software tools become more numerous and
distributed.

        There is a set of Emacs-Lisp ("elisp") code, called
"ange-ftp.el", which makes 'ftp' use transparent within GNU Emacs (GNU
Emacs is available via anonymous ftp from prep.ai.mit.edu). This
package attempts to make accessing files and directories using FTP
from within GNU Emacs as simple and transparent as possible.  A subset
of the common file-handling routines are extended to interact with
FTP. Using these routines, one is able to access remote files and one
would any other local file, without having to write it locally to
disk. The result is an immense virtual global filesystem.
        The routines are available via anonymous ftp (naturally!) as
tut.cis.ohio-state.edu:/pub/gnu/emacs/elisp-archive/as-is/ange-ftp.tar.Z,
(incidentally, if you already had "ange-ftp.el", you could paste the
above line in response to Emacs' 'copy-file', stick "/anonyous@" in
front of it, and copy the file.) My current version is dated 22
October 1991.
        Another useful bit of elisp is "saveconf.el". It saves the
Emacs buffer list and window configuration between editing sessions.
So, one can have several buffers, with several files open (as I
usually do), quit and restart Emacs, and have the state preserved,
cursor locations and windows included. Happily, it works well with
"ange-ftp.el", so that even remote files are restored (after possibly
having to prompt for passwords). "context.el" is also available via
anonymous ftp from cis.ohio-state.edu, as
pub/gnu/emacs/elisp-archive/saveconf.el.Z. Also look for
"tree-dired.el" which provides for hierarchical directory editing.
        Incidentally, it was very easy to produce references for the
above tools, thanks to another tool called "archie", developed at
McGill University. Dubbed a "resource discovery tool" by its authors,
it comes in very handy when one knows what tools are needed but not
their availability. Archie consists of a server for this information
(basically from a database of directory trees from "all known"
anonymous ftp sites, updated once per month), and a client, which may
be run via 'telnet' from the server machine itself (frowned upon...),
or from a standalone client available from that machine (...highly
encouraged, for the considerable host load win). Some clients even
perform ftp tasks based on user response to search results. There are
clients available for dumb and X terminals as well as for (of course)
Emacs. Poke around archie.mcgill.ca for a client and documentation.

	Porting these tools (or at least new interfaces to them) to
Smalltalk would be a great project. I'm working on it in my spare
time. I'd love to hear from any interested people.


-Craig


---

1.0) 	[Archival]

---

1.1)		What free or low-cost Smalltalk implementations are
			there? How can I get GNU Smalltalk?

Answer:

	GNU Smalltalk is free. The most current location, to my
knowledge, is anonymous@prep.ai.mit.edu:pub/gnu/smalltalk-1.1.1.tar.Z.
Please direct problems to the author, Steven Byrne, at
sbb@eng.sun.com.

	Little Smalltalk, by Timothy Budd, is available as a book and
sources, at bookstores. It is also available as
anonymous@cs.dal.ca:pub/comp.archives/little-smalltalk.

---

1.2)		What Smalltalk archives are there?

Answer:

	There are many. Most of them simply archive GNU smalltalk, but
there are also a few large archives containing many interesting and
varied sources. All of the sites may be retrieved by invoking 'archie
smalltalk' (see above reference to 'archie'). 
	For convenience, descriptions of a few of the archives follow.
If you have a site/announcement you'd like included, please let me
know.


**

Directory: anonymous@xcf.berkeley.edu:misc/smalltalk
Summary:
	
	Smalltalk FAQ, smallmusic discussion archive.

**

Host: mushroom.cs.man.ac.uk
Summary: The Manchester Smalltalk archive. Information about it is
	posted regularly to comp.lang.smalltalk.

**

File: anonymous@st.cs.uiuc.edu:pub/Index
Summary: Information about the UIUC Smalltalk archive (which has local
	files and a mirror of the Manchester archive).

**

File: anonymous@ccrma-ftp.stanford.edu:pub/st80/README
Summary: Information about various Smalltalk-related offerings,
	including the Musical Object Development Environment (MODE).


---

2.0) 	[Projects]

---

2.1)		What is Smallmusic?

Answer:

	A work group has formed to discuss and develop an
object-oriented software system for music. The current environment is
Smalltalk 80. The email address for the group is
smallmusic@xcf.Berkeley.EDU.  If you are interested in joining the
discussion, email smallmusic-request@xcf.Berkeley.EDU, with the
subject line "add me".

	The abstract and outline to a recent version of our working
paper follows. The document is available via ftp as
anonymous@ccrma-ftp.stanford.edu:pub/st80/OOMR6.t.


	Thanks,

	Craig Latta
	latta@xcf.Berkeley.EDU

***

Abstract to the working document

	This document describes an object-oriented description
language for musical parameters, events and structures known as the
Smallmusic Object Kernel (SmOKe) .  In object-oriented software terms,
the representation is described in terms of software class hierarchies
of objects that share state and behavior and implement the description
language as their protocol. 
	The authors believe this representation, and its proposed
linear ASCII description in Smalltalk-80 syntax, to be well-suited as
a basis for: (1) concrete description languages in other languages,
(2) specially-designed binary storage and interchange formats, and (3)
use within and between interactive multi-media, hypermedia
applications in several application domains.

	There is an article about an environment implementing SmOKe,
called the Musical Object Development Environment (MODE), in the
Computer Music Journal, volume 16 number 3. There's an "outrageously
sexy" screen shot of the MODE on the cover.

---

2.2)+		What is CoolDraw?

Answer:

Newsgroups: comp.lang.smalltalk
From: bnfb@csr.uucp (Bjorn Freeman-Benson)
Subject: CoolDraw - HotDraw with Constraints (or ThingLab: The Next Generation)
Organization: University of Victoria, Victoria, BC, Canada
Date: Tue, 6 Apr 93 05:15:29 GMT

A while back I saw a query in this group about updated version of ThingLab.
Well, I'm happy to announce that although the name has changed, the
philosophy is the same, and CoolDraw is now available via anonymous FTP.
Here is the READ.ME:

CoolDraw Release 3 Documentation    	    	    	 5-Apr-93

I. What is CoolDraw?

CoolDraw is a constraint-based object-oriented drawing framework.  CoolDraw
is similar to other MacDraw-like packages with one major exception:
everything in CoolDraw is done with constraints.  The user interface is
done with constraints.  Constraints can be added between figures.  Even the
constraint debugger (a future feature) will be done with constraints.  The
total integration of constraints makes it "pretty darn cool".  The system
is written in ParcPlace Smalltalk-80 release 4.1.

CoolDraw is similar to other systems such as IntelliDraw, Chimera, and
Briar.  Also note that CoolDraw is a technology demonstration and research
tool -- not a fully debugged product.  Occasionally it requires some loving
care.  And, quite naturally, it has some unimplemented features.

II. How do I use it?

Open a CoolDrawingEditor using the "open" message.  On the left is a tool
palette.  The top tools are the usual drawing tools: selection, move to
front, move to back, erase, etc.  The middle tools are figure creation
tools: line, rectangle, ellipse, and so on.  The bottom four tools are the
constraint creation and deletion tools: three for creation (one variable,
two variable, and three variable constraints) and one for deletion.

While you automatically use constraints by just creating figures and moving
them around on the screen (because the entire system uses constraints
internally), if you want to create explicit constraints, you have to use
one of the tools.  The cursor of the tool changes to indicate how many
figures have been selected and when enough are selected a dialog box
appears with a standard selection of constraints.  If you want some other
constraint, then press the "Custom" button and a second dialog box offering
a complete selection of constraints will appear.

When the constraint deletion tool is clicked on a figure, it offers a list
of all the explicit constraints attached to that figure.  Any number can be
selected and deleted at once.

III. How do I get it?

Anonymous FTP from ursamajor.uvic.ca in ~ftp/ursa/constraints/CoolDraw
There are two options.  Get the image:
    cooldraw.image.tar.Z
or get the source code:
    cooldraw.source.tar.Z

IV. What are the bugs?

Numerous.  The major flaws are that the constraint system is not currently
powerful enough to solve cycles or simultaneous equations, and that there
is not a large selection of figures.  Minor ones include that the three
constraint tool is not implemented.

The most noticable un-bug is that the constraints do not always do what you
expect.  This is a well-known problem is constraint research and has no
known solution short of a mind-reading computer.  The constraint
hierarchies that CoolDraw uses can help, and future versions will have more
default weak constraints to create "expected" behavior.

V. What are the future plans?

We intend to continue work on three fronts: (1) fix the details (make more
figures available; fix the dialog boxes; provide a wider assortment of
built-in constraints; implement the three constraint tool; etc.); (2)
improve the constraint solver to deal with more complex constraints yet
retain its efficiency; (3) add other cool things such as constraint
debugging tools, animation, etc.

VI. What else should I know?

Without explicitly inspecting the drawing, there is no access to the
internal consistency constraints of the figures.

VIII. Credits and Copyright

See the startup screen.

The CoolDraw code is copyright 1993 by Bjorn N. Freeman-Benson, and its
commercial use is restricted.  For information about the HotDraw or SkyBlue
code, contact the respective authors: Ralph Johnson and Michael Sannella.

Naturally, we would be happy to hear from anyone who uses, plays around
with, or just looks at the system.  

Regards,
Bjorn N. Freeman-Benson

---

3.0) 	[References]

---

3.1)		Can someone recommend a good introduction to
			Model-View-Controller concepts?

Answer:

From: ege@blitz.fiu.edu (Dr. Raimund K. Ege)
Newsgroups: comp.lang.smalltalk
Subject: Re: MVC -- good introductions?
Date: 8 Mar 92 18:26:40 GMT
Organization: Florida International Univ.

Look at Chapter 10 in the following book that just came out:

Programming in an Object-Oriented Environment,
by Raimund K. Ege

Academic Press, Inc., San Diego, CA, 1992, hardcover,
ISBN 0-12-232930-9

To order call 1-800-321-5068.

(also: Academic Press Limited, London, United Kingdom)

It presents a complete and thorough introduction to all object-oriented
concepts. It contains a large
example/case study, and a comparison of major OO programming languages. 

In addition, the book extends the object-oriented view
to all elements of the programming environment: data structures
and algorithms, programming tools, user interfaces, data bases and
software design. 

Chapter 10 is on user interfaces: it describes and illustrates
the Smalltalk MVC paradigm (also: InterViews)

-- 
Raimund K. Ege                             School of Computer Science
                                             Florida Int'l University
ege@scs.fiu.edu           (305) 348-3381              University Park
ege@servax.bitnet     FAX (305) 348-3549              Miami, FL 33199

**

From: asmundvn@dcs.glasgow.ac.uk (Nils Erik Asmundvaag)
Newsgroups: comp.lang.smalltalk
Subject: Re: MVC -- good introductions?
Date: 11 Mar 92 10:56:38 GMT
Organization: Glasgow University Computing Science Dept.

The book

	Smalltalk-80: A Practical Introduction
	(ISBN 0-273-03105-8)

	by Philip D. Gray & Ramzan Mohamed, 1990
	and published by Pitman (at least in the UK)

contains two chapters on interactive applications and the MVC.

I found it very helpful when first learning about the MVC.

Nils E. Asmundvaag

-- 
-------------------------------------------------------------------------------
Nils Erik Asmundvaag 	   		         
University of Glasgow, Scotland
asmundvn@dcs.glasgow.ac.uk      asmundvn@uk.ac.glasgow.dcs


**

From: bruce@utafll.uta.edu (Bruce Samuelson)
Newsgroups: comp.lang.smalltalk
Subject: Re: how are st80 views and controllers used?
Date: 12 Mar 92 14:12:48 GMT
Organization: UTexas at Arlington, Linguistics

There are two papers on MVC that provide an introductory overview of
the pre-version 4.0 ST80 scheme.  Much of what's in them also applies
to version 4.0.  I understand that one of PPS's priorities in the
forthcoming version 4.1 will be improved documentation.  We'll see how
well they explain the new windowing scheme launched in version 4.0.
It would certainly be helpful to get an overview of what's going on
before plunging into the source code of the myriad new classes.

(1) A Cookbook for using the Model-View-Controller User Interface
Paradigm in Smalltalk-80 by Glenn E. Krasner and Stephen T. Pope,
Journal of Object-Oriented Programming, volume 1 number 3, pp. 26-49,
1988

(2) Applications Programming in Smalltalk-80: How to Use
Model-View-Controller (MVC) by Steve Burbeck, Softsmarts, Inc.,
copyright 1987.

The second paper is probably no longer available.  I think Softsmarts
is the company that used to sell a version of Smalltalk for 80286
machines but went out of business some years ago.  The phone number on
the paper is listed as 415-327-8100 (Palo Alto, California).  You may
try asking ParcPlace (or, less likely, Digitalk) if they have copies
of Burbeck's paper.

--
**********************************************************
* Bruce Samuelson	Department of Linguistics	 *
* bruce@ling.uta.edu	University of Texas at Arlington *
**********************************************************


---

3.2)		Is there a Smalltalk bibliography?

Answer:

	There are many... here is one:

From: schultz@grebyn.com (Ronald Schultz)
Newsgroups: comp.lang.smalltalk
Subject: Smalltalk Relevant Texts
Date: 10 Jan 92 16:08:05 GMT
Organization: Grebyn Timesharing


A list of Smalltalk-relevant texts.  Retrieved from the Digitalk
forum on Compuserve.  If you know of any additional texts, please
let me know.  Thanx.


==========================================================================
Ron Schultz                                  
Berard Software Engineering, Inc.            
Columbus Ohio Office                           Headquarters
5634 Claire Court                              301 Lakeforest Drive
Dublin, Ohio 43017                             Gaithersburg, Md. 20877
Phone  (614) 798-0295                          (301) 417-9885  
FAX    (614) 798-0296                          (301) 417-0021
=========================================================================

Smalltalk 80 The Language, Adele Goldberg & David Robson
        Addison-Wesley 1989             ISBN 0-201-13688-0

Smalltalk 80 The Interactive Programming Environment, Adele Goldberg
        Addison Wesley 1984             ISBN 0-201-11372-4

Smalltalk 80 Bits of History, Words of Advice , Glenn Krasner
        Addison Wesley 1984             ISBN 0-201-11669-3

Inside Smalltalk Volume I, Wilf Lalonde & John Pugh
        Prentice Hall 1991              ISBN 0-13-468414-1

Inside Smalltalk Volume II, Wilf Lalonde & John Pugh
        Prentice Hall 1991              ISBN 0-13-465964-3

Object-Oriented Graphics, P. Wisskirchen
	Springer-Verlag 1990		ISBN 3-540-52859-8

Practical Smalltalk: Using Smalltalk/V, Dan Shafer and Dean A. Ritz.
        Springer-Verlag                 ISBN 0-387-97394-X

Rapid Prototyping for Object Oriented Systems, Mark Mullen
        Addison Wesley 1990             ISBN 0-201-55024-5

Object-Oriented Design, Peter Coad and Ed Yourdon
	Yourdon Press 1991		ISBN 0-13-630070-7

Object Oriented Programming for Artificial Intelligence, Ernest Tello
        Addison Wesley 1989             ISBN 0-201-09228-x

The Well Tempered Object, Stephen Travis Pope
        MIT Press 1991                  ISBN 0-262-16126-5

RefTalk/Vwin, David Carl O'Neal
        NuVista Press 1991              ISBN pending

Human-Computer Interface Design Guidelines, C. Marlin Brown
        Ablex Publishing 1989           ISBN 0-89391-332-4

Designing Object-Oriented Software,
                Rebecca Wirfs-Brock, Brian Wilkerson, and Lauren Wiener
        Prentice-Hall 1990              ISBN 0-13-629825-7

Object Oriented Programming with Smalltalk/V, Dusko Savic
        Ellis Horwood 1990              ISBN 0-13-040692-9

An Introduction to Object Oriented Programming & Smalltalk
        Lewis Pinson & Richard Wiener
        Addison Wesley 1988             ISBN 0-201-19127-x

SAA Common User Access Advanced Interface Design Guide
        IBM 1989                        IBM Document # SC26-4582-0

IBM Red Books----(available from your IBM representative
                  contact your local office of IBM and request
                  the placing of an IBM Red Book Order.  If you
                  are an IBM customer, the books are free.  If you
                  are not an IBM customer, the books may have a nominal
                  fee.)----

A Practical Introduction to Object Oriented Programming
        IBM 1990                        IBM Document # GG24-3641

Object Oriented Design - A preliminary Approach
        IBM 1990                        IBM Document # GG24-3647

Developing a CUA Workplace Application
        IBM 1990                        IBM Document # GG24-3580-00

Managing the Development of Object Oriented Applications
        IBM 1990                        IBM Document # GG24-3581-00

Object Oriented Analysis of the ITSO Common Scenario
        IBM 1990                        IBM Document # GG24-3566

CUA Evaluation
        IBM 1990                        IBM Document # GG24-3456

SAA CUA '91 Guide
        IBM 1991                        IBM Document # SC34-4289

SAA CUA '91 Reference
        IBM 1991                        IBM Document # SC34-4290

SAA - A Guide for Evaluating Applications
        IBM 1991                        IBM Document # G320-9803


---

3.3) 		What are the "blue book", "purple book", etc?

Answer:

Date: Wed, 11 Nov 92 12:52:39 PST
From: khaw@parcplace.com (Mike Khaw)


blue
        Goldberg, Adele, and David Robson, _Smalltalk-80: The Language 
        and Its Implementation_, Addison-Wesley, 1983. ISBN
	0-201-11371-6. *Out of print* 
         
orange   
        Goldberg, Adele, _Smalltalk-80: the Interactive Programming 
        Environment_, Addison-Wesley, 1984. ISBN 0-201-11372-4. 
         
green    
        Krasner, Glenn, ed., _Smalltalk-80: Bits of History, Words of 
        Advice_, Addison-Wesley, 1983, ISBN 0-201-11669-3 
         
purple   
        Goldberg, Adele, and David Robson, _Smalltalk-80: The Language_,
        Addison-Wesley, 1989, ISBN 0-201-13688-0 
         
The books are actually cream or tan. The color referred to is the color 
used as the background of the illustration on the front cover (as well 
as for the Addison-Wesley logo on the spine). 
 
The purple book is an update/revision of the blue book, with the 
section on the abstract bytecode machine omitted (because it was out 
of date, according to Adele). 
----------

Mike


---

3.4) 		Who are some employers of Smalltalk programmers?

Answer:

From: johnson@m.cs.uiuc.edu (Ralph Johnson)
Newsgroups: comp.lang.smalltalk
Subject: Smalltalk employers file
Date: 18 Sep 92 16:32:43 GMT
Organization: University of Illinois, Dept. of Comp. Sci., Urbana, IL

	I've noticed a rash of job offers here (I approve of them) and
decided that I should distribute my list of companies hiring
Smalltalkers.  I have collected this over the years and give it to my
students.  However, the size of the list is significantly greater than
the number of my students, so I decided to make it public. I would be
happy to add entries, remove entries, or make other changes to it.  If
you are an employer then you might want to take a look at it to see
whether you like what I say about you, and let me know if you don't.
I'll change it, though I like *short* entries and have shortened
almost everything in here.

	The file is in the Smalltalk archive in
/st-docs/smalltalk-jobs.  You can ftp it from st.cs.uiuc.edu or you
can use the e-mail archive server (see the recent FAQ).  Europeans
note that this will automatically show up in the Manchester archive in
a day or so.

-Ralph Johnson 

---

3.5)		What is the Smalltalk Report?

From: mst@vexpert.dbai.tuwien.ac.at (Markus Stumptner)
Newsgroups: comp.lang.smalltalk
Subject: Opinions on Smalltalk Report (Summary)
Date: 12 Feb 93 11:34:32 GMT
Organization: DB and ES Subdivision, TU Vienna

Ok, here are the comments I received about the Smalltalk Report.
While the sample base is quite small, the response seems
overwhelmingly favorable.  Thanks to all who responded.

	Markus

---------------------------------------------------------------------
I have subscribed since the first issue and I find it to be an excellent
combination of theoretical and practical articles. John Pugh (of LaLonde
and Pugh) is the editor.

On the other hand, I will warn you to expect subscription headaches with
SIGS Publications. They are probably the worst I've ever dealt with and
our technical librarian agrees. They are barely capable of processing a 
renewal let alone a new subscription or problem.
---------------------------------------------------------------------
We subscribe, last issue was about 20 pages, 2 articles, 3 columns.
I would call it a must read publication.
---------------------------------------------------------------------
I think its pretty good. (But then I should mention, I write for it!) It tends
toward intermediate, with lots of practical tips and examples.
---------------------------------------------------------------------
(This was not an answer to my question, but I include it for completeness.)
It is a journal published 9 times per year. Cost in US is $69. Editor
with whom I deal is Paul White (white@scs.carleton.ca). The Smalltalk
Report, Subscribers Services, Dept. SML, PO Box 3000, Denville, NJ
07834-9821.
---------------------------------------------------------------------


-- 
Markus Stumptner                                mst@vexpert.dbai.tuwien.ac.at
University of Technology Vienna                 vexpert!mst@relay.eu.net
Paniglg. 16, A-1040 Vienna, Austria             ...mcsun!vexpert!mst


Newsgroups: comp.lang.smalltalk
From: knight@mrco.carleton.ca (Alan Knight)
Subject: Re: Smalltalk Report
Organization: Carleton University
Date: Mon, 15 Feb 1993 22:30:55 GMT

The Smalltalk report
Subscriber Services Dept SML
PO Box 3000
Denville NJ USA
07834-9821

FAX 212 274 0646

ISSN 1056-7976

US$69/year in e US
US$94/year outside the US

---

3.6)  		Is there a GNU Smalltalk tutorial?

Answer:
	
	Yes. 

From: sbb@laplace.Eng.Sun.COM (Steve Byrne)
Date: 28 Feb 1993 03:00:10 GMT
Organization: Sun Microsystems Inc., Mountain View, CA


	Andy Valencia has very graciously provided an extended
tutorial document describing the Smalltalk language with respect to
GNU Smalltalk.  It covers a wide variety of topics, and provides a
general introduction to object oriented programming concepts.

	You may FTP a copy from the usual GNU locations in a few days
(after it has propagated).  Currently, it may be found at:

    prep.ai.mit.edu: pub/gnu/smalltalk-tutorial.ps.Z  (PostScript)

-or-

    prep.ai.mit.edu: pub/gnu/smalltalk-tutorial.txt.Z  (ASCII)

Check it out -- this looks really good!

Steve

-- 

3.7)+		What's a summary of multiple inheritance in Smalltalk?

Answer:

From: mario@cs.man.ac.uk (Mario Wolczko)
Newsgroups: comp.lang.smalltalk
Subject: Re: Multiple Inheritance in Smalltalk??
Date: 20 Apr 93 12:40:27 GMT
Organization: Dept Computer Science, University of Manchester, U.K.

In article <1qua3qINN9t1@umbc8.umbc.edu>, cs331106@umbc.edu (cs331106) writes:
> 
>   I have been researching the smalltalk language, and have found
> conflicting reports as to whether or not smalltalk is a single
> or multiple inheritance style language.  Any answer would be
> appreciated!

Yes and no, mostly no.  The initial versions of Smalltalk did not have
multiple inheritance.  An MI scheme, written entirely in Smalltalk (ie
not requiring any virtual machine support), was subsequently added.
It is described in
@inproceedings{BorningIngalls82:multipleinheritance,
	author =	"A. H. Borning and D. H. H. Ingalls",
	address =	"Pittsburgh, PA",
	year =		1982,
	booktitle =	"Proceedings of National Conference on
	Artificial Intelligence",
	pages =		"234-237",
	title =		"Multiple inheritance in {S}malltalk-80"
}

This was shipped as part of the Smalltalk-80 virtual image, at least
from version 2.0 (the first "public" release, I believe), through 2.3.
It was removed in 2.4 (or possibly 2.5).  There were several
technical problems with the implementation, and it didn't look like
anyone was really using it anyway.  It was never thoroughly integrated
into the system (eg browsers and other tools).

Mario Wolczko
   ______      Dept. of Computer Science   Internet:      mario@cs.man.ac.uk
 /~      ~\    The University              uucp:    mcsun!uknet!man.cs!mario
(    __    )   Manchester M13 9PL          JANET:         mario@uk.ac.man.cs
 `-':  :`-'    U.K.                        Tel: +44-61-275 6146  (FAX: 6236)
____;  ;_____________the mushroom project___________________________________


---

4.0) 	[Programming issues]

---

4.1) 		What are some "classic Smalltalk bugs", both in the
			system and programmer domains?

Answer:

	See anonymous@st.cs.uiuc.edu:pub/st-docs/classic-bugs, and the
equivalent place on the Manchester archive (see question 1.2 above for
details).

---

5.0) 	["Vendor"-specific issues]

---

5.1) 		How compatible is GNU Smalltalk with Smalltalk-80 (or
			SmalltalkV)?

From: sbb@laplace.eng.sun.com (Steve Byrne)
Newsgroups: comp.lang.smalltalk
Subject: Re: GNU Smalltalk Compatibility
Date: 12 Dec 92 00:52:04
Organization: FSF hackers, Smalltalk division

In article <1992Dec2.182201.11980@ntmtv> irvine@ntmtv.UUCP (Chuck
Irvine) writes:

   How compatible is GNU Smalltalk with Smalltalk-80 (or SmalltalkV)?
   Just curious. Thanks

	This is probably in the FAQ list [it is now...  --crl], but
here goes anyway.  GNU Smalltalk tries to be syntax compatible with
the language described in the blue/purple book (ST-80: the Language*).
I think the only discrepancy is that GNU Smalltalk doesn't allow block
local temporary variables.

Steve

	[Note, however, that the class library for GNU Smalltalk is
very much in its infancy. Most importantly, it has little in the way
of graphical user-interface classes.  --crl]


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End of Smalltalk FAQ

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Craig R. Latta           Experimental Computing Facility                (XCF)
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