jww@bonnie.UUCP (Joel West) (02/08/85)
In the book "Smalltalk-80: The Language and Its Implementation", page x of the preface, the authors state: "The Smalltalk-80 system is based on ideas gleaned from the Simula language and from the visions of Alan Kay..." I know who Alan Kay is, but would someone care to enlighten me as to the similarities and differences between the object-oriented programming of Simula and Smalltalk? I understand the precepts of o-o p fine, have skimmed the discussions of the Smalltalk syntax, but have been unable to find a readable Simula book at my local bookstore. I assume also that someone somewhere has pontificated on this in print. Any references? -- Joel West CACI, Inc. - Federal 3344 N. Torrey Pines Ct La Jolla 92037 jww@bonnie.UUCP (ihnp4!bonnie!jww) westjw@nosc.ARPA (***TEMPORARILY BROKEN***) "The best is the enemy of the good" - A. Mullarney
shebs@utah-cs.UUCP (Stanley Shebs) (02/10/85)
We have been learning Simula in a class this quarter, and I can sum it up as: Object-Oriented Algol. If you just imagine how to do Smalltalk in Algol, you won't be far off the mark. Interesting features of Simula: Lexical scoping for classes and subclasses No "class" objects - a class declaration is a slightly modified procedure declaration, where the methods are declared as subprocedures, and the object creation code (method "new" in ST-80) is the body of the procedure. Objects are assigned to "ref" type variables (pointers) There are probably some other unusual things about Simula that I don't remember right now. Incidentally, all of our material is either xeroxed or notes, so I don't what books one could get. stan shebs
robert@cheviot.UUCP (Robert Stroud) (02/25/85)
I passed some of the recent discussion about Simula and object oriented
programming onto our local Simula expert who asked me to post this reply.
He is referring to an article by Stan Shebs (shebs@utah-cs) which described
Simula as Object-Oriented Algol, or Smalltalk in Algol.
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It was interesting to read Stan Sheb's initial comments on SIMULA.
Rather than describing SIMULA as "Smalltalk in ALGOL" it is more
accurate to call Smalltalk "interactive SIMULA". I would commend
anyone to read "Alan Kay's Magical Mystery Tour" published in, of
all places, the TWA Ambassador flight magazine of January, 1984.
SIMULA has been around in its present form for over 15 years and
some of its concepts go back to the original SIMULA of 1962.
Does everyone know that :
SIMULA is a GENERAL-PURPOSE language,
SIMULA is available on an extensive range of machines,
there is a SIMULA work station called "Mach-S",
there is an international Association of SIMULA Users (ASU),
the next ASU annual conference will be held in Calgary in August, 1985.
If anyone would like more information on SIMULA, please contact:
Ron_Kerr%Newcastle@MIT-MULTICS.ARPA